Document vBZm0m3xyR0z4G4975p2Jwj8w

Chronic Toxicity of Three Polychlorinated Biphenyls in Albino Rats Otis E. Fancher*, M. L. Keplinger, J. B. Plank, E. P. Wheeler2, anti J. C. Calandra Industrial BIO-TEST Laboratories,' Inc. Northbrook, Illinois Running Title; Chronic Toxicity of 3 PCB's in Albino Rats ^ Present Address: 624 N. Abrcgo Drive, Green Valley, Ariz. 85614, to whom proofs are to be sent ^ Monsanto Co. , St. Louis, Missouri HONS 048946 ABSTRACT Chronic Toxicity of Three Polychlorinated Biphenyls in Albino Rats Fanchcr, Otis E, , Keplinger, M. E. , Plank, J. B.# Wheeler, E, P. , anti Calandra, J. C. (0000). Toxicol. Appl. Pharmacol. 00, 00 - 00, Two year toxicity studies were conducted in albino rats with 3 polychlor inalcd biphonyls (Aroclors 1242, J254 and 1260) at dietary levels of 1, 10 and 100 ppm. Each of the three materials at the 100 ppm level caused lever changes characterized by increased liver weights, in creases in liver to body weight and liver to brain weight ratios, and by slight to mild ccntrilobular hypertrophy with fatty vacuolization. These changes were observed only in animals sacrificed after 24 monlhs 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. MOWS 048947 INDEX TERMS Aroclors Aroclor 1242 Aroclor 1254 Arcolor 1260 Polychlorinated biphenyls Chronic toxicity of, in albino rats. Hepatotoxicity of , in albino rats. HONS 046940 Chronic Toxicity of Three Polychlorinated Biphenyls1 in Albino Rats Otis E. Fancher^, M. L. Keplinger, J, B. Plank, E. P, Wheeler'*, and J, C. Cal&ndra Industrial BIO-TEST Laboratories, Incl Northbrook, Illinois Chronic Toxicity of Three Polychlorinated Biphenyls in Albino Rats, Fanchor, Otis E, , Keplinger, M.'L. , Plank, J, B. , Wheeler, E, P, and Cal&ndra, 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 1, 10 and 100 ppm . Each of the llr<cjrnate 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 paper of this series (Fanchcr cl a)., 0000). The present study was conducted in order to determine the effect of long-term, low-level exposure of albino rats to polychlorinated biphenyls of variable chlo i-ino content. MGNS 048949 METHODS AH animals utilized in these studies were weanling albino rats of the Charles River strain obtained from Charles River Breeding Laboratories, North Wilmington, Mass. A control grou p and ni7t^c treat ment groups, each consisting of 50 male and 50 female animals, were employed, (Tlrr<sc 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 NO5'" food consumption was recorded for fiV^ rats of each sex from each *3 group weekly for the first tlire^; months and once monthly for the next nY*e months. Periodic spot checks wore 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 concentra 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 pll and specific . -' , -> gravity wore conducted for five male and five female mis from the control groups and from each hi^h dove level group after 3, 6, 9, 12, IS and \ months of treatment. MGNS 0495o 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 same animals at the same times., A gross autopsy was performed on each animal which died during the study and when feasible tissues were preserved in formalin for histopathologic study. After 3, 6 and 12 months of testing 5/5 animals from each group were sacrificed and subjected to complete gross pathologic examine - 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 hematoxylin-oosin. , At termination of the study after 24 months of treatment the remain ing animals were sacrificed and all wore subjected to gross and micro scopic examination. A tabulation of the incidence of tumor occurrence for each group was made at llie conclusion of the investigation and data relative to location, weight, si/,e and pathologic, classification for eaih tumor wore recorded. MONS 046951 RESULTS A. Body Weights and Weight Gains: Except for a statistically significant (99% confidence level) de pression of weight gain at the 24 - month point for female rats fed 100 ppm of Aroclor 1254jno other effect was observed. B. Food Consumption: Food consumption measurements during the first 12 months of the study and periodic 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. E. Urine Analyses: ; No differences from control data were observed for test animals from any group. F. Pathologic Studies: 1. Three, Six, and Twelve Month Sacrifices. Gross and microscopic findings were not different for control animal;: and animals from any tent group. With each compound organ weights, organ to body weight: ratios and organ to brain weight ratios MOMS 048952 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 eliminations of tissues from control and test animals were those of spontaneous disease commonfor the albino ratj lesions of the trachea and lungs indicative of chronic murine pneumonia. 2. Final Sacrifice & 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 atid liver to brain weight ratios of rats treated at the 100 ppm level, females only in the case of Aroclor 1242. Tin: data for liver weights and ratios arc summarized in Table 1, Statistical evaluations of data for other organs disclosed additional randomly occurring intergroup diffcronccs^but the lack of any consistent dose related response and the absence of any significant histopathologic change.^ indicate that those differences arc probably unrelated to In gestion of 1 he Aroclors. c. Jli sLopalhologio Changes 1. Aroclor 1242 Significant liver changer, wore found in nuimalr fed J 00 ppi MGNS 048953 Aroclor 1242. The compound associated lesions consisted of vacuolar changes, focal hypertrophy and focal hyperplasia. In addition, there wore lesions of inflammation, necrosis, fibrosis and minor degenera tion in this group which, although seen in the controls and lower lest 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 tho presence of fat. The vacuolar lesion in the cytoplasm of these cells was posit ively identified as fat. The hypertrophic change found in the liver was focal and often limited to the central lobular area whore groups of cells wore :X swollon to tw^or three times their normal size with clear pinfc 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 infill ration seem in the livers of control and treated animals are lesions of spontaneous dis ease and not related to tho Aroclor 1242. This level of liver disease is not. unusual in old animals. MQNS 046954 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. AH 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 those given above for Aroclor 1254. The most ^ & V' sever'hyperplastic changes in the transitional epithelium of thcbladf\ dor were associated with the presence of mineralized calculi in the bladder lumen. 3. Aroclor 1260 The histopathologic changes observed were analogous to those described above for Aroclor 1242 except that hyperplasia of the urinary bladder was not observed. / Tho occurrcnceof 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 cither incidence or severity make it doubt ful that the bladder lesions are related to treatment with the Aroclors. D, Tumor Findings Tumor data revealed no indication that any of Ike Aroclors are HONS 040955 carcinogenic. The incidence of tumors and the tumor types for all groups, including tho 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. Tumors 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. DfsCUSSION ` 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 monlhs^and was not associated with functional changes in SAP or SGPT. In all cases the severity of (he 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 ic judged that 10 ppm is a no-offoct level for each of the thrive Aroclors MONS 048956 TABLE 1 Liver Weight and Ratio Data for Albino Rats Treated with Aroclors 1242, 1254 and 1260 Test Material Dietary level (ppm) Liver Weight (g) Males F cmales Liver/Body Wgt. Ratio (g/100g) Males F emalcs Liver/Brain Wgt. Ratio (g/lOOg) 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. 18 3.95 2. 99 3.21 4. 7 5a 3.40 3. 74b 4.67a 3.05 3. 00 3. 19 4. 32a 3-10b 3. S4b 8. 62a 3. 35 3. 19 4. 42a 10. 10 9. 97 10.20 11.90 8'76b 11.40 14. 10a 9.93 11.20 13.4Za 8.42 8.03 8.50 . 11.60a 8. 31 10.30 17.10a 8.62 9.26v 11.60b MQNS 0 4 8 9 5 7 Statistically significant at the 99 percent confidence level b Statistically significant at the 95 percent confidence level xcst Material TABLE 2 Occurrence of Hepatic Fatty Vacuolization in Albino Rats Treated with Aroclors 1242, 1254 and 1260 1 r 1 Dietary Level (ppm) Incidence of Fatty Vacuolization Male Av. Grade Female Av, Grade None Aroclor 1242 Aroclor 1254 Aroclor 1260 1 10 100 1 10 100 1 10 100 0/11 0/13 2/13 3/ 6 1/11 3/12 . 3/11 0/11 2/10 2/10 2/14 -- 0/14 i 0/13 i 11/14 i 3/22 i 1/12 i 10/15 -- 1/14 2 5/15 2 5/15 1 -- -- 1 2 1 1 2 1 1 MONS 0 4 8 9 5 8 Grading System: 1, 0,: minimal; 2 - mild; 3 - moderate; 4 = severe; 5 = extreme TABLE 3 Urinary Bladder Lesions cf AU>ino Rats Treated with Arodors 1212, 1254 and 1260* 1 Test Material Dietary Level (ppm) Animals .Examined None Aroclor 1242 Aroclor 3254 Aroclor 1260 1 10 100 1 10 100 1 10 100 25 25 24 19 29 26 27 21 21 24 Focal Epithelial Hyperplasia Incidence Av. Grade Focal Epithelial Hyperplasia with Cystitis Incidence Av. Grade ii -- -- i -- -- 1 -- --- -- -- 2 -- -- 1 -- -- -- ___ 2 2 -- 1' 2 1 -- -- -- 1. 5 2 -- 3 3 2 -- -- -- Grading System: 1 = minimal; 2 = mild; 3 = moderate; 4 = severe; -5 = extreme HONS 0 4 8 9 5 9 TABLE 4 Tumor Findings Among Albino Rats Treated with Aroclors 1242, 1254 and 1260 Test Material None Aroclor 1242 Aroclor 1254 Aroclor 1260 Dietary Level (ppm) No. of Animals Examined _ 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 Animals with Tumors 9 2; 13 10 17 2 19 14 14 1 17 13 4 0 65 15 1 16 13 13 0 13 11 12 3 15 15 10 0 10 7 12 0 12 9 9 3 12 11 FOOTNOTES l Aroclors 1242, 1254 and 1260. Monsanto Company, St. Louis, Missouri. ^ Present Address: 624 North Abrego Drive, Green Valley, Arizona 85614 3 Monsanto Company, St. Louis, Missouri HONS 048961 REFERENCES '^4:/'' Fanchcr, Otis E. , Kcplinger, M. E. , Wl^cler, E. P. , and Calandra, J. C. (0000). Toxicollgicalifctudies of*|hrce polychlorinated Biphenyls. A' Toxicol. Appl. Pharmacol. 00, 00 - 00. MONS 04*962