Document RpVjoyweVbJEpyK8rBDmk6kqz
FUNDAMENTAL AND APPLIED TOXICOLOGY 6, 105-144 (1986)
Chronic Toxicity and Oncogenicity Study on Inhaled Vinylidene Chloride in Rats
j. F. Quast, M. J. McKenna, L. W. Rampy, and J. M. Norris' Health and Environmental Sciences. The Dow Chemical Company. 1803 Building. Midland. Michigan 48674
Chronic Toxicity and Oncogenicity Study on Inhaled Vinylidene Chloride in Rats Quast, J. F., McKenna, M, J,, Rampy, L. W.. and Norris, J. M. (1986). Fundam. Appl. Toxicol 6, 105-144. Male and female Sprague-Dawley rats (Spartan substrain) were exposed to vinylidene chloride (VDC) by inhalation for 18 months to assess chronic toxicity and oncogenic potential of the subject test material. Interim sacrifices were performed at 1.6, and 12 months. Rats were exposed to VDC concentrations of 10 and 40 ppm for 6 hr/day, 5 days/week for the first 5 weeks of the study. Based upon the absence ofobservable treatment-related effects among rats sacrificed after 1 month of exposure, the exposure concentrations were increased to 25 and 75 ppm VDC. Exposures were continued at these concentrations through the 18th month of the study after which the surviving animals were held until 24 months and then sacrificed. Cytogenetic evaluations were performed on a separate group of animals, four rats/sex, exposed to 0, 25, or 75 ppm VDC for 6 months. There were no exposure-related changes in the following parameters: mortality, appearance and demeanor, body weight data, clinical chemistry determinations, hematologic evaluations, urinalysis, or cytogenetic evaluation of bone marrow preparations. A target organ effect, characterized by hepatocellular fatty change in the midzonal region of the hepatic lobule which was minimal in severity, was observed in both male and female rats of both the 25- and 75-ppm exposure groups as early as the 6-month interim sacrifice. The midzonal fatty change was also observed at the 12-month sacrifice but no indication ofprogression ofthis lesion in either severity or incidence was apparent. During the last 6 months of the study, after exposures had been discontinued, this effect was no longer discernible: therefore this alteration was readily re versible. The incidences of several tumors and/or tumor types were statistically increased or decreased in VDC-exposed rats when compared to their respective control groups: none of these differences were judged to be attributable to VDC exposure. C ism Society orToxmioty.
Vinylidene chloride (1,1 -dichloroethylene:, CH2 = CC12; VDC) is used extensively as a monomeric intermediate in the production oif polymers, particularly in commercial resiniss and films for food packaging. Within the pas;t decade there have been numerous studies res' ported on the evaluation ofthe chronic toxicityy and/or oncogenicity of vinylidene chloride inn laboratory animals exposed via oral, inhala tion, and dermal routes and by subcutaneous injection. The liver is the primary target organ1 for toxicity of vinylidene chloride in rats, rab- bits, dogs, and/or monkeys exposed via thee oral or inhalation routes (Prendergast et al.,,
1 To whom all correspondence should be addressed.
1967; Cage, 1970; Rampy el al., 1977; Quast et al., 1983). In mice exposed via inhalation, the target organs are the liver and kidneys (Lee et al., 1978; Maltoni, 1977). Laboratory investigations of the oncogenic potential of Vi nylidenc chloride have been conducted on rats via inhalation and ingestion (Maltoni. 1977; Viola and Caputo, 1977; Lee el al., 1978; NCI/ NTP, 1982; Hong et al, 1981; Quast et al.. 1983; Maltoni et al, 1982), on hamsters via inhalation (Maltoni, 1977) and on mice via inhalation, ingestion, dermal application, and subcutaneous injection (Maltoni, 1977; Lee et al., 1978; Van Duuren etal., 1979; NCI/NTP, 1982; Hong et al., 1981). Preliminary findings reported by Lee et al. (1978) suggesting an on-
]05 0272-0590/86 S3.00 Copyright C by the Society of TowcoJof), AJI nghtt of reproduction in am form roerved.
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106 QUAST et al.
cogenic response in the rat were not confirmed in subsequent reporting (Hong et al., 1981) or in studies conducted by the other investigators. Evidence of an oncogenic response to vinylidene chloride is limited to a preliminary report of kidney tumors of male Swiss mice exposed to 55 ppm, but not 10 ppm VDC in an in halation study (Maltoni, 1977). The oncogenic response was associated with significant injury to the kidney tissue. Studies on the effect of vinylidene chloride on DNA synthesis and DNA repair in the mouse kidney suggest that the kidney tumors arose primarily as a result of the recurrent tissue injury (Reitz et al., 1980).
The objectives of the present study were twofold. One objective was to assess the chronic toxicity of vinylidene chloride in the rat over an 18-month period and the revers ibility of the target organ toxicity over a 6month postexposure period. The other objec tive was to investigate the oncogenic potential ofthe chemical. This study represents the lon gest inhalation exposure duration used in a laboratory investigation on toxicity and on cogenicity of vinylidene chloride to date. In terim results ofthis study have been previously published (Rampy et al., 1977).
METHODS
Experimental design Male and female Sprague-Dawley rats (Spartan substrain).1* 6* to 7 weeks ofage, were assigned to treatment groups using a table of random numbers. The animals were housed, according to sex, two or three per cage. Food1 and tap water were available ad libitum other than during exposure periods. During nonexposure periods, the animals exposed to VDC vapors were main tained in a holding room which was controlled for tem perature. humidity, and lighting cycle. The control animals were maintained in the holding room throughout the study.
Exposures were 6 hr/day, 5 days/week for 18 months with interim sacrifices at 1,6, and 12 months. Animals remaining after 18 months of exposure were allowed to survive until 24 months, at which time they were sacrificed.
1 Spartan Research Animals, Hasiett, Mich. 1 Purina Laboratory Chow, Ralston Purina Co., St Louis, Mo.
TABLE 1 Numbers of Rats/Sex/Exposure Group
Exposure group (ppm)
0 25 75
Chronic study 1-Month interim sacrifice4 6-Month interim sacrifice 12-Month interim sacrifice 6-Month cytogenetic evaluation
Total number rats on study
86 85 44 55 55 44
104 103
86 4 5 5 4
104
* Exposure levels during first month of exposure were 0, 10, or 40 ppm.
Initially the exposure concentrations of VDC were 0. 10, and 40 ppm. A group of animals were sacrificed at 1 month for evaluation of possible toxic effects. Since no treatment-related effects were noted, the concentrations were changed to 0, 25, and 75 ppm on Day 43 ofexposure. These concentrations were maintained throughout the re mainder of the 18-month exposure portion of this study. A separate group of rats was exposed to 0. 25. or 75 ppm VDC for 6 months for cytogenetic evaluation of femoral bone marrow cells.
The numbers of animals used in the various portions of the study are given in Table I.
Test material. Production-grade vinylidene chloride used in the study was supplied by The Dow Chemical Company. The material was 99% pure as determined by gas chromatography and was stabilized with hydroquinone monomethylether.
Exposure chambers, vapor generation, and analyses. Exposures were conducted in 3.7-m1 stainless-steel cham bers under dynamic airflow conditions. Vinylidene chlo ride vapor atmospheres were generated by metering the liquid test material into a glass vaporization flask at a con trolled rate. The temperature of the flask was maintained at approximately 30C The concentrated VDC vapor was swept by tempered, filtered air into the exposure chamber at an airflow rate calculated to produce the desired con centration.
Analysis ofthe chamber atmosphere was normally per formed 2-5 times during the 6-hr daily exposure period. Analyses were conducted by vapor phase infrared spec trometry. A Perkin-Elmer Model 12A infrared spectro photometer was employed, a path length of 10 m and a wavelength of 12.6 tim were used for the analysis. Chamber concentration was determined by interpolating from a standard curve using peak height measurements. Standards were prepared by injecting a known volume ofvinylidene chloride into a bag made of Saran4 resin which was filled with a measured amount of filtered, compressed air.
4 Trademark of the Dow Chemical Co.
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VDC INHALATION STUDY IN RATS
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Clinical observations. Animals were observed daily during the exposure period for changes in appearance or demeanor and signs of eye or nasal irritation. Individual body weights were recorded weekly for the first month of exposure, biweekly during the second month ofexposure, and a minimum of monthly thereafter. Body weights of animals fasted overnight were measured at the time of scheduled sacrifices. Records ofmortality were maintained. Blood was collected for routine hematology from the tail vein offive animals/sex/exposure group shortly before the 6- and 12-month interim sacrifices and 10 animals/sex/ exposure group at the terminal sacrifice. Hematology pa rameters included red blood ceil count (RBC). hemoglobin concentration (HgbL packed cell volume (PCV), and total and differential white cell count (WBC). Clinical chemistry determinations on serum of blood collected from the cer vical vessel during the necropsy procedure at the interim sacrifices and on S animals/sex/exposure group at the ter minal sacrifice included serum glutamic pyruvic trans aminase (SGPT). blood urea nitrogen (BUN),.and alkaline phosphatase (AP). Blood glucose was also determined at the 12-month interim sacrifice, repeated for confirmation
/ ABLE 2
Selected Cumulative Percentage of Mortality Data on Female Rats
Months on study
No. of tats*;
Exposure level (ppm)
0 25 84 86
75 84
TABLE 3
Mean Body Weights of Male and Female Rats at Selected Times
Exposure level (ppm)
Months on study
0
25
75
Males 0 1 3 6 9 12 15 18
21 24
Females 0 1 3 6 9 12 15 18
21 24
276 276
283*
399 386* 396
489 469* 488
562 529* 549
598 555* 565*
639 593* 586*
638 623
646
627 586* 618
607 582
563*
587 550
530
210 212
203*
259 259
264
294 301* 309*
333 343* 342*
340 348
348
368 377
363
386 391
402
396 419
426
443 412
449
427 463
439
* Statistically different from control mean by analysis of variance and Dunnett's test, a * 0.05.
6
MD*
1 (1)
1 (1)
8
Ml)
Ml)
Ml)
9
Ml)
3(4)
Ml)
11
2(2)
6(7)
MD
12
2(2)
6(7)
5(6)
13
4(5)
9(11)
6(7)
14
4(5)
10(12)
7(8)
15
5(6)
18(21)*
13(16)*
16
8(10)
19(22)*
16(19)
17
9(11)
19 (22)*
18(21)*
18
16(19)
29 (34)*
20 (24)
19
23(27)
37 (43)*
29 (35)
20
30(36)
49 (57)*
41 (49)
21
39(46)
55(64)*
51(61)*
22
46(55)
59 (69)*
54(64)
23
56 (67)
65 (76)
61 (73)
24
64(76)
72 (84)
68(81)
* Excludes rats used for interim sacrifices and cytogenicity study.
* Number dead (% dead). * Statistically different from controls by Fischer's exact probability test, a - 0.05.
of a suggested treatment-related response at 18 months on blood obtained by orbital sinus puncture on 5 animals/ sex/exposure group, and determined on all remaining an imals at the terminal sacrifice.
Urinalyses. Urine samples were obtained from 10 anmals/sex/exposure group shortly before the 6- and 12month interim sacrifices and 10 animals/sex/exposure group at the terminal sacrifice. Urinalyses included deter minations of specific gravity, pH. glucose, protein, ketones, occult blood, bilirubin and. at the terminal sacrifice only, urobilinogen. Specific gravity measurements were made using a T.S. Meter.5 All other measurements were made using Bililabstix.*
Cytogenetic analyses. Animals, four/sex/exposure group, scheduled for cytogenetic analysis were added to the study following the 1-month interim sacrifice. These rats, caged separately, were exposed to 0, 25, or 75 ppm
5 American Optical Co., Buffalo, N.Y. * Ames Co.. Elkhart, Ind.
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108 QUAST ET AL.
VDC for 6 months. At the end of the exposure period and 4 hr prior to sacrifice, the animals were injected interperitoneally with 4 mg/kg colchicine. Femoral bone marrow cells obtained from each rat were processed using Hank's balanced salt solution, a 0.5% K.C1 solution, and a 10% acetic acid in methanol fixative (Legator et al.. 1969). The cells were scored for chromosomal aberrations according to established guidelines (Buckton and Evans. 1973).
Postmortem evaluations. A complete gross pathologic examination was performed on each rat regardless of whether the rat died during the study, was culled in mor ibund condition, or was submitted at the time of a sched uled sacrifice. Rats submitted alive were anesthetized with methoxyflurane and sacrificed by exsanguination. The following tissues were removed and placed in neutral buff ered 10% Formalin: accessory sex glands, adipose tissue, adrenals, aorta, bone marrow (sternal), brain, epididymes.
esophagus, heart, intestines (large and small), kidneys, liver, lungs, lymph nodes (mesenteric, mediastinal), mammary gland, nasal turbinates, ovaries, oviduct, pancreas, para thyroid, peripheral nerve, pituitary gland, prostate, salivary glands, skeletal muscle, skin, spleen, spinal cord, sternum, stomach, testes, thymus, thyroid gland, trachea, urinary bladder, uterus, and any gross lesion or mass. Eyes of rats which died or were culled from the study were preserved in Formalin. Eyes of a portion ofthe rats from the interim or terminal sacrifices were fixed in Zenker's fixative with the remainder in Formalin.
Statistical evaluation Body weight data, clinical chem istry. hematology, urinalysis (specific gravity), and organ weight data were analyzed using analysis of variance and Dunnett's test (Steel and Torrie, I960). Data for cumu lative mortality, incidence of gross and microscopic pathological findings, and tumor incidence were analyzed
Month sacrifice Males
6
12
24
TABLE 4 Selected Hematology Parameters of Rats at 6-, 12-. and 24-Month Sacrifices
Exposure level (ppm)
No. of rats
PCV (%)
RBC (XIOVmm3)
Hgb (g/100 ml)
WBC (XIOVmm1)
0
5
53.7 (3.1)*
8.00 (0.49)
17.1 (0.8)
11.1 (1.2)
25
5
53.2 (0.4)
7.46 (0.56)
17.4(0.4)
10.3 (2.1)
75
5
54.4 (0.5)
7.70 (0.66)
17.3 (0.3)
16.8(13.1)
0
5
50.6(1.7)
8.48 (0.44)
16.4 (0.6)
94(1.8)
25
5
50.6 (2.9)
8.46 (0.28)
17.1 (0.8)
7.7 (2.1)
75
5
53.1 (0.7)
8.92 (0.32)
17.4 (0.5)
10.2 (2.6)
0
10
45.3 (8.1)
7.51 (l.l)
14.6(2.1)
18.7 (7.2)
25
10
43.4 (6.5)
7.09(1.1)
14.4(2.1)
17.3 (6.9)
75
10
47.3 (5.3)
7.61 (0.67)
15.6(1.4)
15.1 (4.8)
Females 6
12
12*
24
0 25 75
0 25 75
0 25 75
0 25 75
5
51.7(3.4)
7.34 (0.48)
16.5 (0.5)
5
49.7 (3.7)
6.65 (0.52)
16.2(1.3)
5
52.7 (3.3)
7.72 (0.90)
17.4 (0.8)
5
46.5(1.5)
7.34 (0.22)
15.3 (0.4)
5
48.3 (2.9)
7.74 (0.46)
15.8(1.1)
5
46.4(1.1)
7.84 (0.15)*
15.5 (0.3)
5
46.9(1.2)
7.32 (0.26)
15.2 (0.3)
5
45.1 (2.8)
7.39 (0.60)
14.9 (1,1)
5
45.8 (3.1)
7.46 (0.56)
15.0(1.1)
10
39.0 (6.9)
6.04(1.3)
12.7 (2.4)
10
39.9 (8.5)
6.34(1.41)
13.4 (2.9)
10
41.3(3.4)
6.66 (0.49)
13.8(1.0)
* Mean (SD). * Additional samples taken 3 days later. * Statistically different from control mean by analysis of variance and Dunnett's test, a = 0.05.
10.0 (2.2) 8.0(3.11 9.6 (1.4)
7.2 (1.5)
4.0(1.or
6.6 (1.3)
7.5 (1.4) 6.4 (1.2) 9.6 (1.0)
13.2 (4.8) 15.1 (6.8) 14.3 (5.4)
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VDC INHALATION STUDY IN RATS
109
by the Fischer's exact test (Siegel. 1956). The level of sig nificance chosen was a 0.0J.
RESULTS
Vapor Analyses
The mean chamber concentrations stan dard deviations during the first month were 9.5 2.5 and 35.8 6.2 ppm VDC. From months 2 to 18, the mean chamber concen trations standard deviations were 25.4 4.6 and 72.6 7.5 ppm VDC.
Clinical Observations
No eye or nasal irritation or changes in ap pearance and demeanor were observed in the animals during the study. Intercurrent murine pneumonia was observed among animals of both sexes during the last 6 months of the study.
Cumulative percentage of mortality data on male rats did not reveal increases as a result of exposure to VDC. Statistically significant non-dose-related mortality increases were ob-
TABLE5 Clinical Chemistry Values at 6.12,18. and 24 Months
Months on study
Males 6
12
18
24
Exposure level (ppm)
0 25 75
0 25 75
0 25 75
0 25 75
No. of rats
SGPT (mU/ml)
5 31.0(7.0)' 5 27.0 (4.0) 5 30.0(12.0)
5 44.4 (4.4) 5 47.4 (5.6) 5 40.4 (5.5)
5 5 5
13 34.0 (6.0) 13 58.0 (63.0) 8 40.0(9.0)
BUN (mg/100 ml)
17.6 (0.9) 22.2(7,1) 16.6 (2.0) 15.5 (3.0) 18.5 (6.2) 17.0 (5.6)
29.0 (8.0) 60.0 (67.0) 32.0(17.0)
AP (mU/ml)
109 (20.0) 124 (26.0) 114 (11.0) 85.6(12.7) 104.6 (30.2) 111.2 (26.8)
94.0 (24.0) 106.0(33.0) 99.0(15.0)
Females 6
12
18
24
0 25 75
0 25 75
0 25 75
0 25 75
5 28.0 (2.0) 26.3 (3.0) 108.0(33.0)
5 29.0 (6.0) 26.2 (0.8) 119.0(69.0)
5 22.0 (6.0) 22.2 (4.5)
80.0(12.0)
5 37.4 (5.8) 18.0(5.5) 5 37.4 (5.7) 14.9 (5.5) 5 38.4(9.9) 14.5(1.7)
70.6(16.6) 65.6(17.6) 77.2(17.1)
5 5 5
19 37 (12) 11 37 (7) 16 32 (8)
30 (30) 22 (10) 36 (54)
124 (95) 94 (79) 92 (55)
* Mean (SD). * Significantly different from control mean by analysis of variance and Dunnett's test, a - 0.05.
Glucose (mg/100 ml)
134.6 (9.6) 124.8 (9.4) 102.8 (7.0f 92.0(16.0) 90.0 (6.0) 96.0 (6.0) 103.0(18.0) 105.0 (26.0) 93.0(19.0)
135.8 (8.6) 137.0(12.2) 137.4(14.6) 100 (9.0) 94.0(10.0) 97.0 (7.0) 101 (23) 89 (29) 95 (20)
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no QUAST ET AL,
served among the female rats exposed to 25 ppm during the 15th through the 22nd months of the study. A trend toward increased cu mulative percentage of mortality was noted in the female rats exposed to 75 ppm from the 14th through the 24th months of the study; the increases were statistically significant at months 15, 17, and 21 (Table 2).
The mean body weights for male rats ex posed to 25 ppm vinylidene chloride were sta tistically lower than the control group for the first 13 months of exposure to VDC. Subse quently, mean body weights of this group re mained lower than controls although they were not statistically decreased in a consistent fashion (Table 3). Male rats of the 75 ppm exposure group showed decreased mean body weights from 6th through the 12th month of the study. A general trend toward decreased mean body weight for animals ofthis exposure group when compared to controls was ob served from the 17th through the 24th month of the study; however, statistically significant differences were only observed at the 17th- and 21st-month weighings.
The mean body weights of female rats ex posed to either 25 or 75 ppm VDC were gen erally found to be statistically significantly greater than control means for the first 6 months of the study (Table 3). Subsequent to this period, no consistent effect on body weight could be noted which was attributed to ex posure to VDC.
Hematology
The results of hematology determinatior performed at the scheduled sacrifices on male rats exposed to either 25 or 75 ppm vinylidene chloride revealed no effects which could be attributed to vinylidene chloride exposure (Table 4). Hematology data obtained on fe male rats exposed to 25 ppm VDC for 1 year indicated a decreased total white blood cell count when compared to the control mean (Table 4). Samples obtained at the same time interval for female rats exposed to 75 ppm in dicated a statistically significant increase in
total red blood cell count when compared to control mean. To verify the repeatability of these observations, the same animals were sampled approximately 3 days following the scheduled 1-year hematology sampling; none of the aforementioned observations were noted. The observations were attributed to normal variation in these measurements and were not judged to be related to vinylidene chloride exposure.
Clinical Chemistry
Clinical chemistry determinations ofserum glutamic pyruvic transaminase, blood urea
table 6
Cytogenetic Evaluation of Femoral Bone Marrow Cells
Exposure No. of
group
rats
Sex
Number of cytogenetic abnormalities/number
of cells scored
Control
4
Male
Control
4
Female
25 rrr'
' Male
4 Female
75 ppm
4 Male
75 ppm
4 Female
Q/34 0/23 0/40 0/38
0/0 0/50 0 0/40
0/50 0/29 0/50
0/39 0/35 0/50 0/28
0/50 0/50 0/50 0/50
0/50 0/32 0/50 0/50*
* One rat died spontaneously poor to the time of eval uation.
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VDC INHALATION STUDY IN RATS
111
nitrogen, and alkaline phosphatase conducted on rats at the interim and terminal sacrifices were not statistically different than the values obtained on the control animals. Blood glu cose determinations performed at the 12month interim sacrifice were statistically sig nificantly decreased only for the male rats exposed to 75 ppm VDC, Blood glucose de terminations repeated at 18 months and at the terminal sacrifice were comparable to control values (Table 5).
Urinalysis
Urinalyses performed on randomly selected animals from the 25 or 75 ppm VDC exposure
groups at the 6- and 12-month interim sacri fices and at the terminal sacrifice did not reveal any consistent effects which were relatable to vinylidene chloride exposure.
Cytogenetic Evaluation
Cytogenetic evaluation of femoral bone marrow cells revealed no chromatid or chro mosomal aberrations in either the control or the VDC-exposed groups of rats. The number of cells scored for each group of animals is given in Table 6. Although 50 good metaphase spreads were not found on the slides prepared for all the animals, sufficient representative spreads were found among some animals in each group.
Months on study
Males 6
12
24
Exposure level (ppm)
0 25 75
0 25 75
0 25 75
TABLE 7 Selected Organ Weights in Male and Female Rats
No* of rats
Body weight (g)
Liver 8 g/lOOg
Kidney t g/IOOg
5
553 (42)*
15.22(3.56)
2.73 (0.42) 3.77 (0.51)
0.68 (0.06)
5
522 (29)
13.81 (1.86)
2.64 (0.22) 3.63 (0.36)
0.70 (0.03)
5
520 (0.48) 13.23(1.63)
2.54 (0.18) 3.57 (0,52)
0.69 (0.06)
5
660(44)
20.57 (1.51)
3.13(0.34) 4.39(0.51)
0.67 (0.12)
5
576 (48)*
15.28 (2.10)* 2.65 (0.23) 3.94 (0.39)
0.69 (0.06)
5
563 (41)*
15.13(2.06)* 2.69 (0.29) 4.04(0.51)
0.72 (0.09)
13
527 (78)
18.28 (1.95)
3.50 (0.37) 5.85(1.08)
1.14(0.30)
13
495 (85)
16.92 (2.94)
3.44 (0.41) 5.33 (0.93)
1.10(0.24)
8
492(61)
16.96 (2.54)
3.44 (0.24) 5.41 (0.78)
1.11 (0.16)
Females 6
0 25 75
5
327(14)
7.25(1.15)
2.22 (0.35) 2.03 (0.28)
0.62 (0.09)
5
303 (50)
6.94(1.27)
2.29 (0.20) 1.88(0.31)
0.62 (0.05)
5
327(17)
7,47 (0.77)
2.28(0.14) 2.06(0.14)
0.63 (0.05)
12
0
5 329(19)
7.45 (0.69)
2.26 (0.11) 2.09(0.10)
0.63 (0.03)
25
5
366 (26)
8.39 (1-.51)
2.32 (0.55) 2.44 (0.26)* 0.67 (0.11)
75
5
340(38)
9.04 (0.80)
2.67 (0.21) 2.60(0.18)* 0.77 (0.09)
24
0
21* 402 (95)
13.47 (4.17)
3.37 (0.76) 2.94 (0.49)
0.77 (0.23)
25 13* 418(109) 15.39(3.77) 3.26 (0.51) 2.96 (0.63) 0.75 (0.24)
75
16
404(72)
13.99 (4.39)
3.47 (0.90) 3.10(0.55)
0.80 (0.26)
* Mean (SD). * Four female rats from either the control or 25-ppm group were unidentified at the terminal sacrifice. For completeness of the data the organ weights of these were included, two in each of the two groups. * Significantly different from control means by analysis of variance and Dunnett's test, a - 0.05.
SL 066201
Number of rats necropsied during the time period indicated
Liver Foci of eosinophilic ground-glass appearing cells
Area ofeosinophilic ground-glass appearing cells
Foci of clear cell hepatocyles
Foci of basophilic hepalocytes
Foci of mononuclear cells within the portal area or lobule
Cenlrilobular degeneration
Atrophy without fatty change
Focal necrosis
SL 066202
TABLE 8 Nontumcwous Histopathologic Lesions in Female Rats
Control 25 ppm 75 ppm
0-6 Months
, J 1
7-12 Months
1 5 4
13-18 Months
14 23 15
19-24 Months
49 46 48
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 mim 75 ppm
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 0 0
0 0 0
0 0 1
1 0 0
0 1 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 1 0
0 I 0
0 t 0
0 1 0
0 15 1 11 24
22 04 11
00 01 00
0I 00 00
6 14 96 44
1 10 3 10 3 13
I 22 5 14 1 19
15 23 13
Terminal kill
19 11 16
10 3 10
3 1 0
2 0 0
0 0 0
7 3 4
0 1 0
2 5 8
I 0 1
Cumulative results
84 86 84
25 15* 16
7 5 2
2 1 0
1 0 0
27 19 13*
12 15 16
25 26 28
7 6 5
QUAST ET AL.
4
Focal vascular dilatation with hepatocellular alteration
Control
0
0
0
0
25 ppm
0
0
0
0
75 ppm
0
0
0
0
Multiloculated biliary cyst
Control
0
0
0
25 ppm
0
0
0
75 ppm
0
0
i
1 3 0
Fatty change--portal to midzonal
Control
I
0
0
t
regions most predominant
25 ppm
0
0
0
0
75 ppm
0
0
0
0
Fatty change--occasional individual
Control
0
0
I
2
hepatocytes
25 ppm
0
0
0
0
75 ppm
0
]
I
0
Fatty change--moderate to severe.
Control
0
0
0
i
involves several lobes to varying
25 ppm
0
0
0
0
degrees
75 ppm
0
0
I
0
Fatty change--some within hepatocytes
Control
0
0
0
0
of lobule--minimal
25 ppm
0
0
2
I
75 ppm
0
0
I
0
Fatty change--focal area(s) or foci
Control
0
0
0
I
25 ppm
0
0
I
0
75 ppm
0
0
I
2
Fatty change--diffuse multifocal areas
Control
0
0
0
I
25 ppm
0
0
0
0
75 ppm
0
0
0
0
Fatty change--midzonal in location
Control
0
0
0
0
25 ppm
0
0
6
0
75 ppm
0
2
5
I
Total number of animals with fatty
Control
1
01
6
change
25 ppm
0
0
9
t
75 ppm
0
3
93
SL 066203
0 0
2 2
0 0 0
2 2 0
0 0 0
2 0 t
2 t 0
0 0 0
0 0
7 3
0 0
2 S 3
2
0
0
5 2
s
23
x
t
> r
0
> H
1O
23
3 2
ca-<
33
2 3
(/!
0
o
6 8*
13 13 16
w
T
Number of rats necropsied during the time period indicated
Focal biliary hyperplasia
Extramedullary hematopoiesis
Periportal hypertrophy
Periportal fibrosis (biliary) and/or sclerosis
Biliary hyperplasia with or without fibrosis
Sinusoidal vascular dilatation
Capsular sclerosis secondary to diaphragmatic hernia
Hematocyst formation beneath the capsule
SL 066204
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
TABLE 8--Continued
0-6 Months
, 1 1
7-12 Months
1 5 4
00 00 00
00 02 12
00 02 02
00 00 00
00 00 00
00 00 00
00 00 00
00 00 00
13--(8 Months
14 23 15
, 2 1
6 4 4
6 8 6
0 0 0
0 0 0
0 0 1
0 0 0
0 0 0
19-24 Months
49 46 48
0 1 1
10 14 17
15 8 9
1 0 1
4 3 1
6 3 2
1 0 0
0 0 1
Terminal kill
19 II 16
1 0 0
9 2 4
7 2 1
0 0 0
2 0 0
5 0 5
0 0 0
0 0 0
Cumulative results
84 86 84
2 3 2
25 22 28
28 20 18
1 0 1
6 3 1
11 3' 8
1 0 0
0 0 1
Cenlrilobular atrophy
Control 25 ppm 75 ppm
1 0 0
0 10 16 3 13
0 8 12
13 2 4
Cenlrilobular necrosis
Control 25 ppm 75 ppm
0 0 0
0 0 0
18 39 0 10
0 I 0
Aggregates of hematogenous pigment containing material in cells
Control 25 ppm 75 ppm
0 0 0
0 0 0
00 00 00
I 0 0
Portal area cells with more eosinophilic staining affinity with or without swelling
Control 25 ppm 75 ppm
0 0 0
0 2 4
00 I|
00
0 0 0
Respiratory system Trachea Focal subepithelial lymphoid infiltrate
Chronic or acute tracheitis
Exudative material in lumen
Lungs Focal chronic interstitial pneumonitis
Focal peribronchiolar mononuclear cell infiltrate
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
0 0 0
0 0 0
1 0 0
0 0 0
0 I l
0 42 0 0t
10
0 08 0 2 15 0 1 22
0 00 I 00 0 00
0 13 0 00 0 03
0 II 42 4 20 28 4 14 29
0 0 0
3 4 3
0 0 0
0 0 0
IS 7 12
066205
SL
40 19* 24'
9 13 10
1 0 0
0 4 4
6 1 2
II 21* 26"
1 1 0
4 0 3
68 60 60
Lh
VDC INHALATIO N STUDY IN RATS
Number of rats necropsied during the time period indicated
Focal areas of alveolar histiocytosis with or without exudation of alveolar macrophages
Acute suppurative pneumonia
Alveolar mineralization
Focal granulomatous inflammatory reaction in lung
Cholesterol cleft formation in lung
Pulmonary changes consistent with cardiac or renal failure; edema; interstitial thickening and fibrosis. inflammatory cell infiltrate and exudation ofcells into alveoli, with or without atelectasis
Focal areas of pleuritis
SL 066206
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
TABLE 8--Continued
0-6 Months
7-12 Months
11 |5
14
00 00 01
10 01 00
00 00 00
00 00 00
00 00 00
00 00 00
15-18 Months
14 23 15
9 13 6
0 0 0
0 0 0
0 1 0
1 0 0
0 0 0
19-24 Months
49 46 48
30 21 21
0 0 0
0 1 0
0 0 0
0 0 0
5 3 3
Terminal kill
19 11 16
15 5 9
0 0 0
0 0 0
0 0 0
0 0 0
2 0 2
1 0 00
00
10
00
00
0 0 0
Cumulative results
84 66 84
54 39* 37
1 1 0
0 1 0
0 I 0
1 0 0
7 3 5
1
0
QUAST ET AL.
Chronic murine pneumonia
Control 25 ppm 75 ppm
0 o o
o
o o
6
16 19
Interstitial fibrosis
Control
o
o
00
25 ppm
o
o
00
75 ppm
o
0
0
1
Macrophages in lumen ofalveoli
Control
o
0
0
0
containing hematogenous pigment
25 ppm
o
0
I
75 ppm
o
0
04
Acute bronchitis
Control 25 ppm 75 ppm
o o o
0 0 0
00 10 00
Urinary system Kidney Minimal degree of chronic nephropathy
Control
o 9 36
25 ppm
0
3
15 33
75 ppm
4 8 32
Moderate degree of chronic nephropathy
Control 25 ppm 75 ppm
0
0 0
0 0 0
47
29
4 14
Severe degree ofchronic nephropathy
Control 25 ppm 75 ppm
0 0 0
0 0 0
03 0l 0t
End-stage kidney
Control 25 ppm 75 ppm
0 0 0
0 0 0
00 10 01
Focal mononuclear cell infiltrate
Control 25 ppm 75 ppm
0 0 0
0 0 2
42 00 20
Multifocal mononuclear cell infiltrate
Control 25 ppm 75 ppm
0 n o
0 0 0
l0 00 00
SL 066207
2
4
2
1 0 0
0 2
0 0 0
8 7 5
7 2 7
4 2 4
0 0 0
0 0 0
0 0 0
9 21' 22"
I 0
2 6
0 1 0
54 58 50
IS 13 25
7 3 5
0 I 1
6 0
4
1 0 0
-~t
VDC INHALATION STUDY IN RATS
TA8LE 8--Continued
Number of rats necropsied during the time period indicated
Control 25 ppm 75 ppm
0-6 Months
1 | 1
7-12 Months
, 5 4
13-18 Months
14 23 15
Mineralized deposits within kidney
Control
0
0
7
tubules, focal
25 ppm
1
4 12
75 ppm
0
0
5
Cortical cyst
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 0 0
Renal tubular epithelial hyperplasia
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 0 0
Acute nephritis
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 0 0
Acquired hydronephrosis Chronic pyelitis Ischemic necrosis
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 1 0
0 0 0
" Significantly different from control dala when analyzed using fisher s exact probability lest, p < fl.OS.
SL 066208
19-24 Months
49 46 48
23 19 17
1 0 0
0 0 0
0 0 1
0 0 1
0 0 0
0 1 0
Terminal kill
19 11 16
6 2 6
0 0 0
1 0 0
0 0 0
0 0 0
0 0 0
0 0 0
oo
Cumulative results
84 86 84
36 38 28
1 0 0 1 0 0
0 0 1
0 0 1
0 1 0
0 1 0
QUAST ET AL.
VDC INHALATION STUDY IN RATS
119
Organ Weights
The only statistically significant changes in organ weights were observed at the 12-month interim sacrifice. Male rats exposed to either 25 or 75 ppm VDC had statistically signifi cantly decreased absolute liver weights with a concomitant decrease in fasted body weights. Female rats had statistically significantly in creased absolute kidney weights at 25 or 75 ppm VDC (Table 7). The biological signifi cance of these observations is questionable since similar changes were not observed at 6 or 24 months.
Pathology
Gross and histologic examination of the re spiratory tissues of male and female rats ex posed to 25 or 75 ppm of VDC revealed a statistically increased incidence of lesions typ ical of chronic murine pneumonia, an infec tious process due to Mycoplasma pulmonis. This disease was first recognized during the 13- to 18-month time interval and increased in incidence as the study progressed. The in cidence of lesions of chronic murine pneu monia was much lower in the control groups. The physical separation ofcontrol and exposed rats in the holding room probably decreased the rate of spread of the infectious disease. In view of the fact that this infectious disease has previously been observed at a higher incidence in control groups from other studies, it was concluded that the chronic murine pneumonia was not the result ofexposure to 25 or 75 ppm of VDC.
As a result of the increased incidence of the more advanced lesions of chronic murine pneumonia noted in lungs of rats exposed to 25 or 75 ppm of VDC, there was a corre sponding statistical decrease in the incidence rates for some of the minor pathologic obser vations in the lungs of rats at both exposure levels as compared to controls, presumably due to masking of the lesions by the pneu monia.
Advanced chronic renal disease was the pri mary cause of death or reason for culling VDC-exposed and control male rats from the study. Female rats frequently were culled from the study because of poor condition due to pressure necrosis, ulceration, and subsequent hemorrhage of subcutaneous tumors in the mammary gland region. The female SpragueDawley rat has a high spontaneous incidence of these tumors.
The incidence of histopathologic changes observed in the respiratory system, kidneys, and liver of control and VDC-exposed rats necropsied during the course of the study are present in Tables 8 and 9, Of the organs and tissues examined in this study, changes con sidered to be treatment related were limited to the liver. The liver changes observed on gross pathologic examination were character ized by a pale color with an accentuation of the lobular pattern. Treatment-related histo pathologic finding, characterized as minimal midzonal hepatocellular fatty change, were found in both male and female rats at the 6and 12-month interim sacrifices and in female rats culled or dying during the 18-month ex posure period (Table 10). No unusual inci dence of fatty change was observed in male rats culled or dying during this period or in male or female rats at the terminal sacrifice. Likewise, no unusual incidence of fatty change was observed among those animals submitted to necropsy during the postexposure period, months 18 to 24 (Table 10).
Tumor incidence data showed that there was no increase in any one tumor type in male rats or in the total numbers oftumors, benign and/or malignant, in the male or female rats exposed to VDC when compared with their respective controls (Tables 11 and 12). There was a statistical increase in the incidence of mammary adenocarcinomas in the females exposed to 25 ppm VDC but not at 75 ppm when compared with the controls (Table 13). The incidence of mammary gland adenocar cinoma in controls ofthis study were, however, at the low end of the range of the historical
SL 066209
Number of nils necropsied during the time period indicated
Liver Accentuated hepatic lobular pattern due to centrilobular atrophy
Generalized hepatic lobular atrophy
Accentuated hepatic lobular pattern due to centrilobular atrophy with hepatocellular vacuolization
Foci of intralobular hepatocellular alteration
Area of intralobular hepatocellular alteration
Focal hepatic necrosis
Multifocal hepatic necrosis
Generalized centrilohular degeneration and/or necrosis
r~
Control 25 ppm 15 ppm
0-6 Months
3 4 4
7-- 12 Months
S 3 4
13-18 Months
19 18 19
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
1 1
0
1
1
0
0 0
1
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm
0 0
0
0 0
0
0 0 0
0 0 0
0
2
o662l
04
05
24
06 02
13
22
02 05
00 00 00
00 00 00
01 0I 00
02 00 00
24 14
- ---. -\
19-24 Months
46 47 31
Terminal kill
13 13 8
17 8
21 7 19 7
15 | 13 1
90
21 30 10
16 06
13
00 00 01
00
20 00
20
31 11
50 90
,
Cumulative results
86 85 86
30 34 32
23 17 13*
7 5 7
7
6
4
0
0
1
I
3
0
4 4 2
II 16
QUAST ET AL.
!
(anoxic) with or without associated accentuation of the lobular pattern or associated fatty change Focal biliary hyperplasia
Focal periportal fibrosis
Focal biliary cyst formation
Focal mononuclear cell infiltrate
Focal extramedullary hematopoiesis
Focal vascular ectasia (dilatation)
Minima! hepatocellular fatty change
Moderate hepatocellular fatty change (cenlrilobular and/or midzona!)
Severe hepatocellular fatty change
Increased number of reticuloendothelial cells lining sinusoids (reticuloendothelial hyperplasia)
75 ppm
1
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 0 0
0 0 2
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
SL 066211
0
0 0 0
0 0 0
0 0 0
4 2 3
1 0 1
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
4 10
28 24 25
3 10 7
27
05 03 02
15 36
s 28
13 26
01 14 01
03 02 03
23 0I 36
00 01 I0
01 00 0I
0I 00 0
0
10 4 0
9 5 I
2 2 0
13 12 4
0 0 0
2 0
1
2 1 3
I 0 0
0 0 0
0 0
20 10' 7'
22 13 10*
7 5 2
68 50* 48'
2 5 2
5 2 4
7 2 12
I I I
I 0 I
I 0
VDC INHALATION STUDY IN RATS
i
f
QUAST e t a l .
Number of rats necropsied during the time period indicated
Foci of cystic degeneration of hepalocytes
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Respiratory system Trachea Focal subepilhelial lymphoid infiltrate
Chronic or acute tracheitis
Lungs Chronic pulmonary lesions characterized by edema. interstitial thickening and fibrosis, inflammatory cell infiltrate and exudation of cells into the alveoli, with or without atelectasis (associated with advanced cardiac or renal lesions) Focal alveolar histiocytosis
Peribronchial lymphoid cellular in (ill rate
Control 25 ppm 75 ppm ' onlrol
rwn m
pm
Control 25 ppm 75 ppm Control 2^ ppm ,
, , sl, 066^,
TABLE 9--Confirmed
0-6 Months
3 4 4
7-12 Months
5 3 4
00 00 00
13-18 Months
19 18 19
0 0 0
00 00 00
00 20 10
01 00 00
5 0 1 1 4 3
7
1.
22 02 03
8 4 3
0 5 17
3 13 2 4 16
-l i
'
'"1
19-24 Months
46 47 51
0 1 0
6 3 4 0 16 15
19 II 15
21 17 14 27 IK
1
Terminal kilt
13 13 8
2 3 2
0 1 0 0 2 2
0 1 0
10 10 3 13 11 ft
Cumulative results
86 85 86
2 4 2
11 4" 5 1 24' 21'
23 12' 15
43 33 23* 62 47' I1)*
VDC INHALATION STUDY IN RATS
Focal interstitial pneumonitis
Control 25 ppm 75 ppm
I 0 0
0 0 0
02 0 04
4 3 I
6 4 5
Focal aggregates of macrophages containing hematogenous pigment within the alveoli
Control 25 ppm 75 ppm
0 0 0
0 0 0
0I I 00
5 4 1
6 6 1
Acute diffuse suppurative pneumonia
Control 25 ppm 75 ppm
I 2 2
0 0 0
00 00 10
0 0 0
1 2 3
Focal granulomatous inflammation
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 00 00
0 0 0
I 0 0
Pieurilis
Control 25 ppm 75 ppm
0 0 0
0 0 0
I0 00 00
0 0 0
0 0
Focal pulmonary abscess formation
Control 25 ppm 75 ppm
0 0 0
0 0 0
10 00 00
0 0 0
0 0
Focal mineralization of the intraalveolar septae
Control 25 ppm 75 ppm
0 0 0
0 0 0
59 I3 36
0 0 0
14 4* 9
Chronic murine pneumonia
Control
0
0
00
0
0
25 ppm
0
0
4 19
3
26*
75 ppm
0
0
3 19
2
24"
Cholesterol cleft formation
Control 25 ppm 75 ppm
0 0 0
0 0 0
00 00 00
0 0
1 0 0
Urinary system Kidney Minimal degree of chronic nephropathy
Control 25 ppm 75 ppm
2 0 0
4 2 4
15 17 14
w
SL 066213
#
* ><v,
TABLE 9--Continued
0-6 Months
7-12 Months
13-18 Months
Number of rats necropsied during the time period indicated
Moderate degree of chronic nephropathy
Severe degree of chronic nephropathy
End-stage kidney
Mineralized deposits within kidney tubules, focal
Focal renal cortical tubular hyperplasia
Acquired hydronephrosis
Pyelonephritis
Focal hyperplasia of the transitional epithelium
Control 23 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
3 4 4
0
0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0
0
5 19 3 18 4 19
,7 05
06
0t
04 04
07 12
06
04
01
03
01 00 00
01
00 00
01 00 00
00
00 00
' Significally different from control data when analyzed using Fisher's exact probability lest, p < 0.03.
19-24 Months
46 47 51
9 11 16
19 15 20
12 14 8
13 9 8
0 0 0
0 1 0
1 1
0
0 0 0
Terminal kill
13 13 8
6 5 5
7 7 3
0 0
0
0 0 0
0
0
0
0 0 0
0 1 0
1 0 0
SL 066214
Cumulative results
86 85 86
23 21 27
27 26 27
19 17 14
17
to 9
l 0 0
1
1
0
2 2 0
1 0 0
oCc>HO mH
> r
: r, ' i1
1
n
VDC INHALATION STUDY IN RATS
125
TABLE 10 Incidence of Midzonal Hepatocellular Fatty Change in Male and Female Rats
No. of animals with fatty change/no. of animals examined
Exposure level (ppm)
Time of examination
0 25 75
At scheduled sacrifice 6-month interim
12-month interim
24-month terminal
At death or following culling During 18-month exposure period During 6-month postexposurt period, but not including 24-month terminal sacrifice
0/5 M 0/5 F
0/5 M 0/5 F
1/13 M 1/19 F
0/27 M 0/16 F
0/46 M 0/49 F
1/5 M 2/5 F
3/5 M 5/5 F
0/13 M 0/11 F
0/25 M 6/29 F
1/47 M 0/46 F
4/5 M 4/5 F
5/5 M 5/5 F
0/8 M 0/16 F
1/27 M 7/20 F
0/51 M 1/48 F
experience for malignant mammary tumors in the Sprague-Dawley rat in this laboratory (Table 14).
There were a number of tumor types that were statistically decreased in incidence in the VDC-exposed groups when compared with the controls. Specifically, in male rats the inci dence of pituitary adenomas was decreased at 25 and 75 ppm levels, and pancreatic islet cell adenomas and thyroid adenocarcinomas were decreased at the 75 ppm level. The incidence ofpituitary adenomas was decreased in female rats exposed at 25 ppm.
The total incidence of histopathologically diagnosed primary tumors, benign and malig nant, from the VDC-exposed groups was comparable to the concurrent control groups and historical control experience of this lab oratory.
CONCLUSIONS
The findings from the initial 5-week phase of the chronic toxicity and oncogenicity study during which rats were exposed to 0, 10, or 40 ppm VDC, 6 hr/day, 5 days/week indicated that concentrations as high as 40 ppm did not
produce signs of toxicity in the target organ, the liver. The findings at the increased con centrations of 25 or 75 ppm indicated that on longer exposure both concentrations were ef fect levels for target organ toxicity. The liver effects, characterized by minimal hepatocel lular fatty changes in the midzonal region of the hepatic lobule, were observed in both male and female rats of both the exposure groups as early as the 6-month interim sacrifice. Midzonal fatty changes were also observed at the 12-month sacrifice, but there was no indica tion of progression of this lesion in either se verity or incidence. By the 18th month of the study the incidence of this change was no lon ger increased in male rats exposed to VDC when compared to controls. However, female rats of the 75-ppm exposure group bad a sig nificantly higher incidence of hepatic fatty change than did their controls and a trend to ward an increased incidence (not statistically significant) was apparent in female rats of the 25-ppm group. During the last 6 months of the study, after exposures had been discontin ued, the effect was no longer discernible in dicating reversibility of the lesion.
066215
SI*
Number of rats necropsied during the time period indicated
Liver Undifferentiated sarcoma with invasion oMung and diaphragm
Metastatic adrenal cortical carcinoma
Respiratory system Lungs Metastatic adrenal cortical carcinoma
Well-differentiated bronchial and/or alveolar carcinoma without metastasis
Metastatic thyroid gland carcinoma
Undifferentiated sarcoma with a pulmonary metastasis
Metastatic mucinous cystadenocaici noma
TABLE I 1 Histopathologic Diagnosis and Number of Tumors in Male Rats
0-6 Months
7-12 Months
13-18 Months
19-24 Months
Control
3
5
19 46
25 ppm
4
3
18 47
75 ppm
4
4
19 51
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 0 0
0 0 0
01 00 00
00 00 00
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Conlrtd 25 ppm 75 ppm
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
01 00 01
00 00 00
00 00 00
00 00 01
00 10 00
Terminal kill
13 13
8
0 0 0
0 0 '
0 0 0
1 0 0
1 0 0
0 0 0
0 0 0
- ''
r --^
0662-16 -7
. -,
-
Cumulative results
86 85 86
i 0 0
0 0 l
1 0 1
1 0 0
1 0 0
0 0 1
0 1 0
QUAST ET AL.
Urinary system Nephroblastoma
Transitional celt papilloma
Gastrointestinal tract Stomach Metastatic adenocarcinoma of probable intestinal origin
Small intestine Mucinous cysladenocarci noma without metastasis
Undifferentiated sarcoma with osseous metaplasia without metastasis
Mucinous cysladenocarci noma with metastasis to lung
Sclerosing adenocarcinoma of probable intestinal origin with metastasis to stomach
Salivary gland Carcinoma, most probably salivary gland in origin without metastasis
Pleomorphic sarcoma of probable salivary gland origin
Pancreas Pancreatic acinar adenoma
SL 066217
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
i oo ooo ooo
ooo ooo ooo
ooo 001 ooo
0 00 001 0 02
00l 0 00 0 00
0 00 0 10 0 00
ooo 0 01 ooo
ooo ooo t 00
0I
0
ooo
ooo
0 3 13 0 23 0 5 12
o o o
0 0
0 0 0
I 0 1
0 0 0
0 0 0
0 0 0
0 0 0 0 0 0
8 t fi
,f'S
i 0 0
1 0 0
0 I
0
<
Is
iz
3
X >
H 0
0
0
3
ca
0 <
z 0
I5
0 -i
0
I 0 0
24 to 6 '-t
21
Number of rats necropsied during the time period indicated
Pancreatic acinar adenocarcinoma without metastasis
Mixed exocrine and endocrine adenoma
Pancreatic islet celt adenoma
Reproductive system Testis Interstitial cell adenoma of the testis
Mesothelioma of the Umica albuginea
Undifferentiated sarcoma without metastasis, most probable neurofibrosarcoma
Nervous system Brain Astrocytoma
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
r -- - r " f - - SL 066218--^
TABLE 11--Continued
0-6 Months
7-12 Months
35 43 44
00 00 00
00 00 00
00 00 00
13-18 Months
19 18 19
0 0 0
0 0 0
1 0 1
19-24 Months
46 47 51
0 2 0
0 0 0
3 1 3
00 00 00
00 00 00
00 00 00
00 00 03
00 00 01
00 01 00
00 00 01
,-------
01 01 00
----- .
Terminal kill
13 13 8
0 0 0
0 1 0
8 2 1
2 1 0
0 0 2
0 0 0
0 0 0
Cumulative results
86 85 86
0 2 0
0 1 0
12 3 5"
2 1 3
0 0 3
0 1 0
1 1 1
Intracranial pleomorphic sarcoma without metastasis
Pituitary Pituitary adenoma
Atypical adenoma
Pituitary adenocarcinoma without invasion of brain
Pituitary adenoma based on gross examination but microscopic section not available for evaluation
Total number of animals with a pituitary tumor
Spinal cord Neurofibrosarcoma within pelvic canal or ventral thoracic region without metastasis
Peripheral nerve Schwannoma in abdominal region-- origin uncertain
Adrenal gland Cortex Adenoma of adrenal cortex
Adrenal cortical carcinoma without metastasis
SL 066219
Control 25 ppm
75 ppm
Control 25 ppm 75 ppm Control 25 ppm 75 ppm
Control 25 ppm
75 ppm Control 25 ppm 75 ppm
Control 25 ppm
75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm Control 25 ppm 75 ppm
0 0 0
0 0 0 0 0 0 0 0 0 0 0 0
0 0 0
0 0 0
0 0 0
0 0 0 0 0 0
0 1 0
0 0 I 0 0 0
0 0 0
0 0 0
0 0
0 0 0
0 0 0
0 0 0 0 0 0
00 00 00
3 16
3s
38
00 0 00
0t 00 00
00 02 00
3 17
3 I! 38
11 00 00
00 00 0I
03 00 0I
00 01 00
0 0 0
4
2 0 0 0 0 0 0
0 0 0
4
I 2
0 0 0
0 0 0
0 0 0 0 0 0
__ > i ,r]l,L
0 I 0
23 12* 14*
0
0
1
0 0
8
0
21
0>
24 15*
oz
14* c
D><
2 0
z
0
w
0 0 I
3
0 I
0 I 0
(It,
Number of rats necropsied during the lime period indicated
Adrenal cortical carcinoma with metastasis to lung
Adrenal cortical carcinoma with ' metastasis to liver
Medulla Adrenal pheochromocytoma, unilateral
Adrenal pheochromocytoma, bilateral
Malignant pheochromocytoma with no apparent metastasis, unilateral
Total number of animals with a pheochromocytoma
Thyroid Thyroid adenoma
Thyroid adenocarcinoma without metastasis
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
TABLE II--CtNKfmmf
0-6 Months
7-12 Months
35 43 44
00 00 00
00 00 00
00 00 00
00 00 00
00 00 00
00 00 00
13-1* Months
19 18 19
0 0 0
0 0 0
3 l 4
0 0 0
0 0 0
3 1 4
00 00 00
00 00 00
0 2 1
| 0 0
r-St-^M0~n '
19-24 Months
46 47 51
, 0 1
0 0 0
14 16 12
* It 7
2 | 2
24 28 21
Terminal kill
13 13 8
0 0 0
0 0 1
5 3 7
3 4 l
1 0 = 0 "9 7 9
45 4 4 51
5| 1l 01
Cumulative results
86 85 86
, 0 1
0 0 1
22 20 23
11 15 8
3 l 2
36 36 34
9 10 7
7 2 r
QUAST ET AL.
Thyroid carcinoma with metastasis to cervical lymph nodes and lung
Total number of animals with a thyroid tumor
Subcutaneous tissue Subcutaneous fibroma
Subcutaneous fibrosarcoma without metastasis
Subcutaneous fibrosarcoma with metastasis to lung
Undifferentiated sarcoma with metastasis to lung
Fibrolipoma
Neurofibrosarcoma
Mammary gland Fibroadenoma/adenofibnMna
Fibroma
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
00 00 00
00 00 00
00 0 1/1 1/1 0
0 I/I 00 00
00 00 00
00 00 00
00 00 00
00 00 00
00 00 00
00 00 00
SL 066221
o o 0
1 2
0 01 0
0
0 0
0
0 1/1
0 0 0
0 0
0
0
0 0
0 1/1
I/I
0 0 0
0 0 0
9 5 5
6/d 4/3 5/4
0 0 l/t
0 0
0
0
0
1/1
0 0 0
0 0 0
0 0 1/1 0 0 0
1 0 0
7 5
2
1/1 0 0
0
0 0
0
0
0
0
0 0
0 1/1
0
0 0
1/1
0 0 0
1/1 0 0
1 0 0
17 12
8`
7/5* 6/5* 6/5*
l/l6 0
1/1*
0 0
1/1*
0 0
1/1*
0
t/1*
0
0 0
1/1*
z
X
r>-
>
doz
3ca<
0 I/I* 2/2*
1/1*
0
Number of rats necruptied during the time period indicated
Integument Sebaceous squamous cell carcinoma of the external auditory canal without metastasis (Zymbal gland carcinoma) Squamous cell carcinoma of the orbit of the eye without metastasis
Undifferentiated sarcoma of probable neural origin without metastasis
Unclassified malignant epithelial neoplasm of the nose ,
Squamous papilloma with keratin ization
Musculoskeletal system Osteogenic sarcoma of the rear limb without metastasis
Hard palate--squamous cell carcinoma
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
TABLE II--Continued
B-6 Months
7-12 Months
35 43 44
00 00 00
00 00 00
00 00 00
00 00 00
00 00 00
13--18 Months
19 IS 19
1 0 0
0 0 0
0 0 0
0 0 0
0 0 0
00 00 00
00 00 00
0 0 0
0 0 0
19-24 Months
46 47 51
1 2 1
1 0 0
0 1 0
0 1 0
0 r.l S
0 0 1
0 0 1
Terminal kill
13 13 8
0 1 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
Cumulative results
86 85 86
2 3 1
1 0 0
0 l 0
0 1 0
0 1 0
0 0 1 0 0 1
06622^
VDC INHALATION STUDY IN RATS
Lymphoreticular system Lymphosarcomas and leukemias Generalized leukemia with multiple tissue metastasis
Lymphosarcoma of the small intestine without metastasis
Lymphosarcoma of the large intestine without metastasis
Thymus Thymoma
Other lymph nodes Metastatic thyroid gland carcinoma to cervical lymph nodes
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 1 0
0 0 0
0 0 0
0 0 0
0 0 0
Total number of primary tumors in the
Control
0
2
14
male rats as previously listed
25 ppm
0
2
12
75 ppm
1
3 16
* Significantly different from control data when analyzed using Fisher's enact probability test, p < 0.05. * Number of tumors/number of animals with tumors.
2 1 2
1 0 0
0 1 0
1 0 0
0 0 0
86 66 71
0 1 0
0 0 0
0 0 0
0 0 0
1 0 0
43 21 24
2 3 2
1 0 0
0 1 0
1 0 0
1 0 0
145 101 115
SL 066223
W
TABU 12 HlSTOfATHOUX3KT DlAGNOSK AND NUMBER OF TUMORS IN FEMALE RaTS
Number of rats necropsied during the time period indicated
Control 25 ppm 75 ppm
0-6 Months
, 1 1
7-12 Months
, 5 4
13-18 Months
14 23 IS
19-24 Months
49 46 48
Liver Cholangioma
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 0 0
Metastatic adenocarcinoma of uterocervi* region
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 0 0
Respiratory system Lung Metastatic leiomyosarcoma of the uterocervi* region
Control 25 ppm 75 ppm
0 0 0
0 0 0
1 0 0
Metastatic adenocarcinoma of uterocervi* region
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 0 0
Metastatic adenocarcinoma of mammary gland region
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 0 0
Metastatic osteogenic sarcoma of the forelimb
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 0 0
Metastatic carcinoma of the thyroid
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 0 0
Metastatic cortical carcinoma of the adrenal gland
f~ -
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 0 0
066224 '
0 0 0
1 0 1
0 0 0
1 0 0
1 0 0
0 0 0
0 l 0
0 0 0
Terminal kill
19 II 16
0 1 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 1
0 0 0
0 1 0
Cumulative results
84 86 84
0 1 0
1 0 1
1 0 0
1 0 0
1 0 0
0 0 1
0 1 0
0 1 0
QUAST HT AL.
Urinary system Kidney Metastatic adenocarcinoma or the uterocervix region
Renal cortical carcinoma without metastasis--well differentiated
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
VDC INHALATION s t u d y in RATS
Cardiovascular system Heart Undifferentiated endocardial sarcoma without metastasis
Blood vessels Metastatic leiomyosarcoma of the uterocervix region--to several blood vessels
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Gastrointestinal tract Stomach Leiomyosarcoma with multiple intraabdominal metastasis
Small intestine Mucinous cystadenocarcinoma without metastasis
Metastatic leiomyosarcoma of the uterocervix region
Metastatic adenocarcinoma of probable uterine origin
Large intestine Metastatic adenocarcinoma or uterocervix origin
SL 066225
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Number of rati necropsied during the time period indicated
Salivary (land Carcinoma moat probably ndivary gland in origin without metastasis
Reproductive system Ovary Granulosa cell tumor without metastasis
Ovarian adenocarcinoma of scterosing type with multiple tissue metastases
Ovarian hemangioma
Metastatic adenocarcinoma of uterocervix origin
Uterus Endometrial polyp formation
Endometrial polyp based on gross examination only
Stromal sarcoma of uterocervix origin without metastasi*
Control 23 ppm 73 ppm
Control 23 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm Control
TABLE 12--OMftMMtf
0-4 Months
7-12 Months
11 15 14
00 00 00
00 00 00
00 00 00
00 00 00
00 00 00
00 01 00
00 00 00
0I 00 00
66226
3-11 Months
14 23 15
0 0
1
0 0 0
0 0 0
0 0 0
0 0 0
1 2 1
0 0 0
0 0 0
19-24 Months
49 46 48
0 0 0
Terminal kill
19 II 16
0 0 0
l 0 0
1 0 0
1 0 0
1 0 0,
' SHfi*
9 2 4
0 0 1
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
3 5 5
1 0 0
0 0 0
Cumulate results
84 86 84
0 0 1
1 0 0
1 0 0
1 0 0
1 0 0
13 10 to
1 0 1
) 0 0
Undifferentiated sarcoma of ulerocervix
Control
0
0
2
0
0
origin without metaslases
25 ppm
0
0
0
0
0
75 ppm
0
0
0
0
0
Leiomyosarcoma of ulerocervix region
Control
0
0
00
with metastasis to lung, small intestine
25 ppm
0
0
0
0
0
and blood vessels
75 ppm
0
0
0
0
0
Adenocarcinoma of ulerocervix origin with
Control
0
0
0
0
multiple tissue metastasis
25 ppm
0
0
0
00
75 ppm
0
0
0
I
0
Endometrial carcinoma of the uterus
Control
0
0
0
I
0
without metastasis
25 ppm
0
0
0
00
75 ppm
0
0
0
0
1
Adenocarcinoma of the uterus without
Control
0
0
0
1
2
metastasis
25 ppm
0
0
0
2
0
75 ppm
0
0
0
0
0
Leiomyoma without metastasis
Control
0
0
0
0
0
25 ppm
0
0
0
0
0
75 ppm
0
0
0
I
0
Cervix--fibroma
Control
0
0
0
0
0
25 ppm
0
0
0
I
75 ppm
0
0
0
0
t
Scirrhous adenocarcinoma, origin
Control
0
0
0
0
0
undetermined, most probable ovary and
25 ppm
0
0
0
0
0
uterine horn with widespread abdominal
75 ppm
0
0
0
0
metastasis
Carcinoma of ulerocervix with metastasis
Control
0
0
0
0
0
to abdominal viscera and one kidney
25 ppm
0
0
0
0
75 ppm
0
0
0
0
0
Nervous system Brain Astrocytoma
Control
0
0
0
1
I
25 ppm
0
0
0
0
0
75 ppm
0
0
0
0
0
Oligodendroglioma
Control
0
0
0
I0
25 ppm
0
0
0
0
0
SL 066227
75 ppm
0
0
0
0
0
2 0 0
0 0
0
t
0
<
3s
2
0z
X
0
> r
0>
t oz
0
2 l
ca
<
0z
0 70
>
0 0
2 0 0
0 u~>4 0
-% oT3
Number of rals necropsicd during the time period indicated
Control 25 ppm 75 ppm
Metastatic lymphoma
Pituitary Pituitary adenoma
Pituitary adenocarcinoma without invasion of brain
Pituitary adenocarcinoma with invasion of brain
Adenoma based on gross examination only
Total number of animats with a pituitary tumor
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Thyroid Thyroid adenoma
Thyroid adenocarcinoma without metastasis
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
-r
- --- SL 066228
TABLE 12--Continued
0-6 Months
1 1 1
7-12 Months
1 5 4
00 00 00
00 00 00
00 00 00
00 00 00
00 00 00
00 00 00
13-18 Months
14 23 15
0 0 0
2 5 2
0 0 0
0 0 0
0 0 0
2 5 2
00 00 00
00 00 00
0 | 2
0 0 0
r-- . f -
19-24 Months
49 46 48
0 1 0
20 13 13
1 1 0
3 0 0
0 I 2
24 15 15
It 9 7
1 0 1
Terminal kill
19 11 16
0 0 0
15 6 11
0 1 0
0 0 0
0 1 0
15 8 II
3 3 7
5 0 0
Cumulative results
84 86 84
0 1 0
oo
QUAST ET AL.
37 24* 26
1 2 0
3 0 0
0 2 2
41 28* 28
14 13 16
6 0* 1
Thyroid carcinoma with pulmonary metastasis
Total number of animals with a thyroid tumor
Parathyroid Parathyroid adenoma
Adrenal gland Cortex Adenoma of adrenal cortex
Adrenal cortical carcinoma without metastasis
Adrenal cortical carcinoma with metastasis to lung
Metastatic adenocarcinoma of uterocervix region
Medulla Adrenal pheochromocytoma, unilateral
Adrenal pheochromocytoma, bilateral
Total number ofanimals with a pheochromocytoma
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 0 0
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 0 0
0 0 0
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 0 0
SL 066229
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
00 0I 00
0 12
t 10 28
00 0I 00
1I 0I 00
0I 00 0I
00 00 00
0I 00 00
02 t3 02
05
00 00
07 13 02
0 0 0
8
3 7
0 0 0
1 1 0
0 0 0
0 I 0
0 0 0
2 0 1
I
I 2
3 I 3
0
0
20 14 17
0 I 0
X
3 2
szc
0>
I
0 oz
0
3c
o<
0
l 0 0
4 4 3
6 1 2
10
5
5 >o
Number of rats necropsied during the time period indicated
Ganglioneuroma--unilateral
Pancreas Pancreatic islet cell adenoma
Metastatic adenocarcinoma of the uterocervix region
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Subcutaneous tissue Subcutaneous fibroma
Subcutaneous fibrosarcoma without metastasis
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Mammary gland Fibroade noma/adcnofibroma
Control 25 ppm 75 ppm
Fibroma
Control 25 ppm 75 ppm
Adenocarcinoma with pulmonary metastasis
Control 25 ppm 75 ppm
SL 066230
TABLE 12--Continued
0-6 Months
, 1 1
7-12 Months
1 5 4
00 00 00
00 00 00
00 00 00
00 00 00
00 00 00
00 0 2/2 l/t 6/4
00 00 00
00 00 00
13-18 Months
14 23 15
0 1 0
0 0 1
0 0 0
0 0 0
0 0 0
17/10 40/20 17/14
0 0 0
0 0 0
19-24 Months
49 46 48
0 0 0
5 0 0
1 0 1
0 0 1 '<
I 0 0
78/39 76/38 100/40
0 0 I/I
I/I 0 0
Terminal kill
19 II 16
0 0 0
1 2 0
0 0 0
0 0 0
I/I 0 0
37/15 16/8 33/15
0 0 1/1 0 0 0
Cumulative results
84 86 84
0 1 0
6 2 1
1 0 1
0 0 1/1*
1/1* 0 0
132/64* 134/68* 157/74*
0 0 2/2*
1/1* 0 0
QUAST ET AL.
Adenocarcinoma without metastasis Leiomyosarcoma without metastasis Carcinoma of the mammary gland Adenofibroma based on gross examination only
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 0 0
0 0 0
00
1/1 2/2 0 2/2
I/I 0
1/1 4/3 0 2/2
0 0 00
0
0 1/1
0
0 0 00
0
0 1/1
I/I*
0 00 0
00 0 0
0 0 00 0 0 00 0 0 1/1 0
Musculoskeletal system
Metastatic adenocarcinoma of the
Control
0
0
0
I
0
uterocervix region to the mandible
25 ppm
0
0
0
0
0
75 ppm
0
0
0
0
0
Osteogenic sarcoma of the forelimb with
Control
0
0
0
0
0
metastasis to the lung
25 ppm
0
0
0
0
0
75 ppm
0
0
0
0
I
Lymphoreticular system Mediastinal lymphoid tissue Metastatic adenocarcinoma of the uterocervix region
Mesenteric lymphoid tissue Metastatic adenocarcinoma of uterocervix region
Spleen Metastatic adenocarcinoma of uterocervix region
Lymphosarcoma and leukemias Generalized lymphosarcoma with multiple tissue metastasis
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
Control 25 ppm
75 ppm
00 00 00
00 00 00
00 00 00
00 00 00
SL 066231
0 0 0
0 0 0
0 0 0
I0 00 I0
10 00 10
0 0 0
00 20 00
I/I* 8/7** 4/4*
0 1/1* 0
0 0 1/1*
I 0 o 0 0 t
1 0 ]
1 o 1
I 0 I
I 2 o
VDC INHALATIO N STUDY IN RATS
TABLE 12--Continued
Number of rats necropsicd during the time period indicated
Control 25 ppm 75 ppm
0-6 Months
1' | 1
7-12 Months
, 5 4
13-18 Months
14 23 15
Monocytic myelogenous leukemia with multiple tissue metastasis
Malignant lymphoma, primarily of mesenteric lymph nodes with intestinal and brain metastasis
Control 25 ppm 75 ppm
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 0 0
0 0 0
0 1 0
0 0 0
Eye Retobulbar fibrosarcoma without metastasis
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 1
0
Adipose tissue Metastatic adenocarcinoma of the ulerocervix region
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 0 0
Miscellaneous Undifferentiated mesenchymal sarcoma of the mediastinal region with extension into the surrounding mediastinal tissue and vessels but without distant metastasis
Control 25 ppm 75 ppm
0 0 0
0 0 0
0 0 0
Total number of primary tumors in the female
Control
0
,
25
rats as previously listed
25 ppm
0
4
54
75 ppm
1
6
26
* Significantly different from control data when analyzed using Fisher's exact probability test, p < 0.05. * Number of tumors/number of animals with tumors.
SL 0662
19-24 Months
49 46 48
0 0 0 0 1 0
0 0 0
1 0 1
1 0 0
149 119 137
Terminal kill
19 11 16
0 0 0 0 0 0
0 0 0
0 0 0
0 0 0
73 43 65
Cumulative results
84 86 84
0 1 0
0 1 0
K>
QUAST et a l .
0 l 0
1 0 1
1 0 0
248 220 235
VDC INHALATION STUDY IN RATS
143
Concentrations of 25 or 75 ppm did not produce exposure-related effects on hematol ogy, urinalyses, clinical chemistry, or cytoge netic parameters. Slight increases in cumula tive mortality were observed in the VDC-exposed female rats throughout the latter portion of the study. There was, however, no indica tion of a dose-response relationship. The higher incidence of murine pneumonia ob served among the animals in both exposure groups as the study progressed was considered to have contributed to this increased mortality. Similarly, body weight decreases observed among the male and female rats were neither consistent or dose related, but may have been associated with the murine pneumonia. The only statistical changes in organ weight mea surements occurred at the 12-month interim sacrifice; a decrease in mean absolute liver weights and concomitant decreased body weights were observed in male rats exposed to 25 or 75 ppm. Comparable effects were not observed in the animals at 1,6, or 24 months. At the 12-month interim sacrifice, female rats at both concentrations had significantly in creased mean absolute kidney weights which were not accompanied by any gross or his topathologic observations. Kidney weight changes were not observed in the female rats at 1, 6, or 24 months. No treatment-related histopathology was observed either at the in terim or terminal sacrifices in the kidneys of rats on this study.
TABLE 14
Historical Incidences of Malignant Mammary Tumors in Control Female Sprague-Dawley Rats
Study
Incidence
1 1/85 2 6/88 3 8/86 4 4/80 5 13/92 6 3/84 7 6/80 8 9/100 9 13/86
Although the incidences of several tumors and/or tumor types were found to be statisti cally increased or decreased in VDC-exposed rats compared to controls, none of these sta tistically significant differences were judged to be attributable to VDC exposure. The majority of pathologic alterations observed in this study were associated with intercurrent disease (murine pneumonia), and commonly found geriatric lesions in this strain of rat, or both. The total incidence of histologically diagnosed primary tumors (benign and malignant) was similar in control and VDC-exposed groups ofboth sexes. In addition, the tumor incidence data for both control and treated rats in this study was comparable to historical control data for the Sprague-Dawley rat (Spartan substrain) used by this laboratory for several studies of similar design and duration.
TABLE 13 Incidence of Mammary Tumors in Female Rats
Exposure level
Controls 25 ppm 75 ppm
No. of rats
84 86 84
Mammary gland adenocarcinoma
2/2*
8/7*
4/4
* Number of tumors/number of animals with tumors. * Significantly different from controls by Fisher's exact probability test, a - 0.05.
ACKNOWLEDGMENTS
The authors thank M. F. Balmer and H. O. Yakel for their technical assistance in the conduct of this study.
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Gage, J. C. (1970). The subacute inhalation toxicity of 109 industrial chemicals. Brit. J. Ind Med. 27, 1-18.
Hong, C. B,, Winston, J. M., Thornburg, L. P.. Lee, C. C., and Woods, J. S. (1981). Follow-up study on carcinogenicity of vinyl chloride and vinylidene chloride in tats and mice. Tumor incidence and mortality sub-
SL 066233
144 QUAST ET AL.
sequent to exposure. J. Toxicol Environ. Health 7,909924. Lee, C. G. Bhandari, J. C., Winston, J. M.. and House, W. B. (1978). Carcinogenicity of vinyl chloride and vinylidene chloride. J. Toxicol. Environ. Health 4, 15-
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1-5.
Maltoni, c., Ciuberti, a., and Carretti, d. (1982). Experimental contributions in identifying brain poten tial carcinogens in the Petrochemical Industry. Ann. N. Y. Acad. Sci. 381, 216-249.
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