Document XOxdx3LyRZ4DJoKw1L5RBZ3zB

Chronic Toxicity of Three Polychlorinated Biphenyls in Albino Rats Otis E. Rancher^, M. E. Keplinger, J. B. Plank, E. P. Wheeler^, and J. C. Calandra Industrial BIO-TEST Laboratories,' Inc. Northbrook, Illinois Running Title: Chronic Toxicity of 3 PC'B's in Albino Rats ^ Present Address; 624 N. Abrego Drive, Green Valley, Ariz. 85614, to whom proofs are to be scut ^ Monsanto Co. , St. Bonis, Missouri DSW 036949 STLCOPCB4020773 ABSTRACT Chronic Toxicity of Three Polychlorinated Biphenyls in Albino Rats. Fanchcr, Otis E. , Keplinger, M, L. , Planlc, J. B. , Wheeler, E. P. , and Calandra, J. C. (0000). Toxicol. Appl. Pharmacol. (K), 00 - 00, Two year toxicity studies were conducted in albino rats with 3 polychlor inated biphenyls (Aroclors 1242, 1254 and 1260} at dietary levels of 1, 10 and 100 ppm. Each of the three materials at the 100 ppm level 9 Ay caused l^ver changes characterized by increased liver weights, in creases in liver to body weight and liver to brain weight ratios, and by slight to mild centrilobular hypertrophy with fatty vacuolization. These changes were observed only in animals sacrificed after 24 months of treatment. No other effects were observed at 100 ppm except for a weight depression for female rats with Aroclor 1254 and no effects were observed with any material at 1 or 10 ppm. OSW 036950 STLCOPCB4020774 INDEX TERMS Aroclor s Aroclor 1242 Aroclor 1254 Arcolor 1260 Polychlo rinoted biphenyls Chronic toxicity of, in albino rats. Ilepatotoxic ity of, in albino rats. Chronic Toxicity of Three Polychlorinated Biphenyls* in Albino Rats 2 Otis E. Fancher , M, L. Keplinger, J. B. Plank, E. P. Wheeler'*, and J. C. Calandra Industrial BIO-TEST Laboratories, Inci Northbrook, Illinois Chronic Toxicity of Three Polychlorinated Biphenyls in Albino Rats. Fancher, Otis E. , Keplinger, M. 'L. , Plank, J. B. , Wheeler, E. P. and Calandra, J. C. (0000), Toxicol. Appl. Pharmacol. 00, 00 - 00. Two year toxicity studies were conducted in albino rats with 3 polychlor- \ inated biphenyls (Aroclors 1242, 1254 and 1260) at dietary levels of 3, 10 and 100 ppm . Each of the llrr-penmate rials at the 100 ppm level caused liver changes characterized by increased liver weights, in creases in liver to body weight and liver to brain weight ratios, and by slight to mild centrilobular hypertrophy with fatty vacuolization. These changes were observed only in animals sacrificed after 24 months of treatment. No other effects were observed at 100 ppm except for a weight: depression for female rats with Aroclor 1254 and no effects were observed with any material at 1 or 10 ppm. Background information has been summarized in the introductory p:ipor of this so ics (Fancher ct al, , 0000), The present study was conducted in order to determine the effect of long-term, low-level exposure of albino rats to tfrix^ polyehlorinated biphenyls of variable chlo rine content. DSW 036952 STLCOPCB4020776 METHODS AT) animals utilised in these studies were weanling albino rats of the Charles River strain obtained from Charles Ilivcr Breeding Lab oratori.es, North Wilmi.ngton, Mass. A control grou. p and nvYric treat ment groups, each consisting of 50 male and 50 female animals, were .3 ,, employed ( t mr-QC treatment groups for each of the 3 Aroclors studied. All diets were prepared fresh each week by mixing the appropri ate Aroclor at levels of 1, 10 and 100 ppm with Purina Rat Chow (Ralston Purina Company, St, Louis, Missouri) in a Hobart Mixer. Each individually housed rat was offered an amount of food sufficient for ad libitum feeding for one week. Unconsumed food was weighed and food consumption was recorded for fiV'""e5 rats of each sex from each .3 group weekly for the first threp months and once monthly for the next ms iiCei months. Periodic spot checks were made thereafter. Water was freely available at all times. Initially the body weight of each rat was determined. Individual weights were determined weekly for 13 weeks and monthly thereafter. Blood studies, including determinations of hemoglobin conccntra - tion, hematocrit value, erythrocyte count and total and differential leukocyte counts, and urine analyses for the presence of glucose, albu min and microscopic elements and determinations of pi I and specific gravity we re conducted for five male and five female rat s from the control groups and from each high dose level group after 3, 6, 9, 1Z, 15 and ,M months of treatment. ` DSW 036953 STLCOPCB4020777 Determinations of blood urea nitrogen concentration (BUN),serum alkaline phosphatase activity (SAP), fasting blood glucose concentra tion and scrum glutamic-pyruvic transaminase activity (SGPT) were determined for the sa3*ne animals at the same tunes.t A gross autopsy was performed on each animal which died during the study and when feasible tissues were preserved in formalin histopathologic study. After 3, 6 and 12 months of testin were sacrificed and subjected to complete gross pathologic examina tions. Organ weights were recorded for liver, kidneys, spleen, gonads, heart and brain and organ to body weight and organ to brain weight ratios were calculated. These data were subjected to an Analysis of Variance and significant: disclosures were further studied by "t"-tests. Microscopic examinations were conducted on 33 tissues from all control and high treatment level animals sacrificed after 3, 6 and 12 months of testing following fixation in 10% formalin and staining with hemal oxyl in-cosin. At termination of the study after 24 months of treatment the remain ing animals were sacrificed and all were subjected to gross and micro scopic examination. A tabulation of the incidence of tumor occurrence for each group was made at the conclusion of the investigation and data relative to location, weight, sir.e and pathologic, classification for each tumor were recorded. DSW 036954 STLCOPCB4020778 RESULTS A. Body Weights and Weight Gains: Except for a statistically significant (99% confidence level) de~ prossion of weight gain at the 24 - month point for female rats fed 100 ppm of ArocJor 1254^no other effect was observed. B. Food Consumption; Food consumption measurements during the first 12 months of the study and j^eriodic checks thereafter revealed no significant differ ences between the control group and any test group. C. Mortality and Reactions; The number of animals dying and the time frequency distribution of deaths did not. differ among treatment and control groups. D. Hematologic and Blood Chemistry Studies; Values for all parameters were within the normal range for the albino rat. No significant differences between values for the control groups and those for any test group were observed, lil. Urine Analyses: No differences from control data were observed for test animals from any group . I1', Pathologic .Studies; 1. Three, Six, and Twelve Month Sacrifices. Gross and microscopic findings were not different for control animals and animals from any tost group. With each compound organ weights, organ lo body weight: ratios and organ to brain weight ratios DSW 036955 STLCOPCB4020779 disclosed several randomly occurring intergroup differences but the lack of any consistent dose related response and the absence of any deleterious histopathologic changes indicate that the differences were not directly related to the ingestion of the Aroclors, The lesions noted in the microscopic examinations of tissues from control and test animals were those of spontaneous disease common for the albino rat; lesions of the trachea and lungs indicative of chronic murine pneumonia. 2. Final Sacrifice a. Gross Pathologic Findings Gross findings for animals from all treated groups were not different from those for control animals. b. Organ Weight and Ratio Data Each of the three Aroclors led to increased liver weights and increases in liver to body weight and liver to brain weight ratios of rats treated at the 100 ppm level, females only in the case of Aroclor 1242. The data for fix er weights and ratios are summarized in Table 1. .Statistical evaluations of data for other orga.ns disclosed additional randomly occurring intergroup diffcrcnccs^but the lack of any consistent dose related response and the absence of any significant histopathologic changes indicate that: these differences are probably unrelated to in gestion of tire Aroclors. c. Histopathologic Changes 1. Aroclor 1212 Significant liver change:; v. ere found in animals fed 100 ppm of OSW 036956 STLCOPCB4020780 Aroclor 1242. The compound associated lesions consisted of vacuolar changes, focal hypertrophy and focal hyperplasia. In addition, there were lesions of inflammation, necrosis, fibrosis and minor degenera tion in this group which, although seen in the controls and lower test groups, were more severe and frequent at the highest treatment level. The vacuolar change^was observed occasionally in the control animals and in animals treated at levels of 1 or 10 ppm "but was observed frequently in animals at the 100 ppm level. The lesion is morphologically indicative .of fatty degeneration. Formalin-frozen sec tions of liver from representative animals which displayed vacuolar changes were stained with Oil Red O to reveal the presence of fat. The vacuolar lesion in the cytoplasm of these cells was positively identified as fat. The hypertrophic change found in the liver was focal and often limited to the central lobular area where groups of cells were :'X X ' swollen to tv<o^or three times their normal size with clear pink homo genous cytoplasm. The hyperplasia was associated with the same cells and appeared to be an extension of the hypertrophic lesion. The hyper plastic cells were also usually hypertrophic. The most severe examples of hyperplasia appeared as nodular growths with limited compression of the surrounding normal hepatic, tissue. Other minor lesions of degeneration, hepatitis, ductile cell proliferation, necrosis and focal lymphoid infiltration seen in the livers of control and treated animals arc lesions of spontaneous dis ease and not related to the Aroclor 1242. This level of liver disease is not unusual in old animals. DSW 03695? STLCOPCB4020781 Hyperplasia of the transitional epithelium was present in the urinary bladder of animals from the control group and from each of the test groups. This lesion was usually associated with cystitis. All of the other lesions in the other tissues found in these animals are related to spontaneous disease and they are not unusual for rats of this age. 2. Aroclor 1254 The histopathologic changes observed may be described - - ........ . in terms identical to those1 given above for Aroclor 1254. The most ":- 65- v sever'hyperplastic changes in the transitional epithelium of theblad- 4 c der were associated with the presence of mineralized calculi in the bladder lumen. 3. Aroclor 1260 The histopathologic change s observed were analogous to those described above for Aroclor 1242 except that hyperplasia of the urinary bladder was not observed, 't The occurrenceof hepatic fatty vacuolization, which is judged to be a treatment related effect, is summarized in Table 2. The bladder findings are presented in Table 3. The occurrence of epithelial hyperplasia in a control animal and the absence of a dose correlation with regard to either incidence or severity make it doubt ful that the bladder lesions arc related to treatment with the Aroclors. D. Tumor Findings Tumor data revealed no indication that any of the Aroclors are . DSW 036958 STLCOPCB4020782 0 carcinogenic. The incidence of tumors and the tumor types for all groups, including the control group, were as would be expected for a random population of rats at the age of two years. The tumor findings are summarized in Table 4. The predominant tumors were abdominal fibroadenomas. Adenomas of the pituitary, thyroid, parathyroid, adrenals and pancreas occurred with much lower frequencies. Turnors judged to be malignant were of random occurrence and included adeno carcinoma of pancreas and abdomen, lymphosarcoma of lymph nodes, spleen or liver and lymphatic reticulum cell sarcoma. . DISCUSSION From the results of this study it is concluded that 100 ppm is an effect level for each of the Aroclors investigated. The target organ is the liver and the effect is characterized by increased liver weights and increased liver/body weight and liver/brain weight ratios and by vac uolar lesions indicative of fatty degeneration. The effect was slow to develop, not being seen among animals sacrificed after 3, 6 or 12 monthr^and was not associated with functional changes in SAP or SGPT. In all cases the severity of the vacuolar changes was judged to be slight to mild (grades 1 or 2 on a 5-point grading system). Since the frequency of occurrence of fatty vacuolization was not greater for animals treated at levels of 1 and 10 ppm than for control animals, it ') is judged that 10 ppm is a no-effect level for each of the thrqe Aroclors. DSW 036959 STLCOPCB4020783 DSW 0 3 6 9 6 0 TABLE 1 Liver Weight and Ratio Data for Albino Rats Treated ' with Aroclors 1Z42, 1Z54 and 1260 Test Material Dietary level (ppm) Liver Weight (g) Males , Females Liver/Body Wgt. Ratio (g/ioog) Males F exnales Liver/Brain Wgt. Ratio ( g/100g) Males Females None Aroclor 1242 Aroclor 1254 Aroclor 1260 1 10 100 1 10 100 1 10 100 22. 0 21.9 22. 3 25.6 19.5 23.9 30. 2a 22. 0 24. 1 29. 9a 16. 3 15.7 17. 1 22. 4a 16. 1 19.5 32. Ia 16.6 18. 1 22. 7a 3.47 2. 93 3. IS 3.95 2.99 3. 21 4. 7 5a 3.40 3. 74b 4. 67a 3. 053. 00 3. 19 4. 32a 3*10b 3. 84b ' 8. 62a ' 3.35 . 3. 19 4. 42a 10. 10 9. 97 10. 20 11. 90 8.76* 11.40 14.10a 9.93 11.20 13.42a 8.42 8. 03 8.50 11.60a 8. 31 . 10.30 17.10a 8.62 9.26 11.60b a Statistically significant at the 99 percent confidence level Statistically significant at the 95 percent' confidence level ' 4 TABLE 2 Occurrence of Hepatic Fatty Vacuolization, in Albino Rats Treated with. Aroclors 1242, 1254 and 1260 i cst Material None Aroclor 1242 Aroclor 1254 Aroclor 1260 Dietary Level (ppm) _ 1 10 100 1 10 100 1 10 100 Incidence of 3[Tatty Vacuolization Male Av. Grade Female Av. Grade 0/11 0/13 2/13 3/ 6 1/11 3/12 . 3/11 0/11 2/10 2/10 2/14 1 -- 0/14 -- 1 0/13 --- 1 ` 11/14 1 1 3/22 '2 1 1/12 1 1 10/15 1 -- 1/14 2 2 5/15 1 2 5/15 1 Grading System: '. 1^0^= minimal; 2 - mild; 3 " moderate; 4 = severe; 5 = extreme D CO s: oU O' vO O' STLCOPCB4020785 TABLE 3 Urinary Bladder Lesions o AUnno Rats Treated with Aroclors 1212, 1254 and 1260 Test Material Dietary Level (ppm) Animal s Examined Focal Epithelial Hyperplasia Incidence Av, Grade Focal Epithelial Hyperplasia -with Cystitis Incidence Av. Grade N one Aroclor 1242 Aroclor 1254 Aroclor 1260 1 10 100 1 10 100 1 10 100 25 25 24 19 29 26 2721 21 24 11 ---- ---- 12 ---- ---- 11 ---- --- -- -- _- 2 1.5 22 ---- i3 23 12 ---- ---- -- --- 1 . Grading System: 1 = minimal; 2 = mild; 3 - moderate; 4 = severe; 5 = extreme a t/j oU! o sO O' IV '- STLCOPCB4020786 STLCOPCB4020787 TABLE 4 Tumor Findings Among Albino Rats Treated with Aroclors 1242, 1254 and 1260 Test Material Dietary Level (ppm) No. of Animals Examined None Aroclor 1242 Aroclor 1254 Aroclor 1260 1 10 100 1 10 100 1 10 100 26 29 27 21 34 24 27 28 23 28 Tumor incidence Benign Malignant Total No. of Anir with Tumors 9 2; 13 10 . 17 2 19 14 14 1 17 13 4 0 .6 5 15 1 16 13 13 0 13 11 12 3 15 15 10 0 10 7 12 0 12 9 9 3 12 11 o ac o OoJ vC O' U) o FOOTNOTES Aroclors 12-12, 1254 and 1260. Monsanto Company, St, Louis, Missouri, a Present Address: 624 North Abrego Drive, Green Valley, Arizona 85614 3 Monsanto Company, St. Louis, Missouri. .. i DS W 036964 STLCOPCB4020788 REFERENCES /\i. -/' (-1 Fancher, Otis E. , Keplinger, M. L. , Wheeler, E. P. , and Calandra, J. C. (0000). Toxicolfgi cal-Sfctudies of*]hr ee polychlorinated Siphenyls, Toxicol. Appl. Pharmacol. 00, 00 - 00. DShl 036965 STLCOPCB4020789