NTP technical report on the toxicology and carcinogenesis studies of vinylidene chloride (CASRN 75-35-4) in F344/N rats and B6C3F1/N mice (inhalation studies)
There was some evidence of carcinogenic activity of vinylidene chloride in female F344/N rats based on increased incidences of C-cell adenoma or carcinoma in the thyroid gland and systemic mononuclear cell leukemia. Occurrences of malignant mesothelioma may have been related to vinylidene chloride e...
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| Format: | eBook |
| Language: | English |
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Research Triangle Park (NC)
National Toxicology Program
August 2015, 2015
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| Series: | NTP TR
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| Online Access: | |
| Collection: | National Center for Biotechnology Information - Collection details see MPG.ReNa |
| Summary: | There was some evidence of carcinogenic activity of vinylidene chloride in female F344/N rats based on increased incidences of C-cell adenoma or carcinoma in the thyroid gland and systemic mononuclear cell leukemia. Occurrences of malignant mesothelioma may have been related to vinylidene chloride exposure. There was clear evidence of carcinogenic activity of vinylidene chloride in male B6C3F1/N mice based on increased incidences of renal tubule adenoma and carcinoma. Increased incidences of hepatocholangiocarcinoma may have been related to vinylidene chloride exposure. There was clear evidence of carcinogenic activity of vinylidene chloride in female B6C3F1/N mice based on increased incidences of systemic hemangioma or hemangiosarcoma (combined). Hepatocholangiocarcinoma and hepatocellular adenoma or carcinoma (combined) in the liver of female mice were also considered to be related to vinylidene chloride exposure. Centrilobular necrosis of the liver was associated with early deaths in male and female rats exposed to 200 or 400\sppm, and centrilobular cytoplasmic alteration of hepatocytes occurred in all exposed male and female rats that survived to terminal kill. The incidences of renal tubule casts in the renal papillae of 200 and 400\sppm rats were significantly increased. CONCLUSIONS: Under the conditions of this 2-year inhalation study, there was clear evidence of carcinogenic activity (see Explanation of Levels of Evidence of Carcinogenic Activity; see summary of the peer review panel comments and the public discussion on this Technical Report in Appendix M) of vinylidene chloride in male F344/N rats based on increased incidences of malignant mesothelioma. Increased incidences of renal tubule carcinoma and respiratory epithelium adenoma in the nose of male rats were also considered to be related to vinylidene chloride exposure. Increased incidences of alveolar/bronchiolar carcinoma in the lungs and carcinoma of the small intestine may have been related to treatment. Exposure to vinylidene chloride caused increases in the incidences of nonneoplastic lesions in the nose of rats and mice, the liver of rats, the lung of male rats, and the kidney\sof\smale\smice. Synonyms: 1, 1-dichloroethene; 1, 1-dichloroethylene TWO-WEEK STUDY IN RATS: Groups of five male and five female rats were exposed by whole body inhalation to vinylidene chloride vapor at concentrations of 0, 25, 50, 100, 200, or 400\sppm, 6\shours plus T90 (12\sminutes) per day, 5\sdays per week for 16\sdays. All male and nine of 10 female rats in the 200 and 400\sppm groups were found dead by day 2; one female in the 400\sppm group was found dead on day 4. All other rats survived until the end of the study except one 25\sppm male was removed from the study due to chylothorax (nonexposure-related condition). The mean body weight gain of 100\sppm females was significantly less than that of the chamber controls. Prior to death, all females and nine of 10\smales exposed to 200 or 400\sppm became lethargic, while all females and four of five males exposed to 400\sppm developed ataxia. Kidney weights of all surviving groups of exposed males and females were significantly greater than those of the chamber controls. |
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| Physical Description: | 1 PDF file (various pagings) illustrations |