Inhalation carcinogenicity of 1,1,1-trichloroethane in rats and mice

• Published in: Inhalation toxicology 2013-04, Vol.25 (5), p.298-306
• Main Authors: Ohnishi, Makoto, Umeda, Yumi, Katagiri, Taku, Kasai, Tatsuya, Ikawa, Naoki, Nishizawa, Tomoshi, Fukushima, Shoji
• Format: Article
• Language: English
• Subjects: 1,1,1-Trichloroethane; Adenoma - chemically induced; Adenoma - pathology; Administration, Inhalation; Animals; carcinogenicity; Carcinogens - administration & dosage; Carcinogens - toxicity; Carcinoma - chemically induced; Carcinoma - pathology; Female; Harderian Gland - drug effects; Harderian Gland - pathology; inhalation; Liver Neoplasms - chemically induced; Liver Neoplasms - pathology; Lung Neoplasms - chemically induced; Lung Neoplasms - pathology; Lymphoma - chemically induced; Lymphoma - pathology; Male; Mice; mouse; rat; Rats; Rats, Inbred F344; Splenic Neoplasms - chemically induced; Splenic Neoplasms - pathology; Toxicity Tests, Chronic; Trichloroethanes - administration & dosage; Trichloroethanes - toxicity
• ISSN: 0895-8378; 1091-7691
• DOI: 10.3109/08958378.2013.780116

Abstract Carcinogenicity of 1,1,1-trichloroethane (TCE) was examined by an inhalation exposure of F344 rats and BDF1 mice of both sexes to TCE at 0, 200, 800 or 3200 ppm for 6 h/d, 5 d/week for 104 weeks. In male rats, the incidences of bronchiolo-alveolar adenomas and peritoneal mesotheliomas were significantly increased in the 800 and 3200 ppm-exposed groups, respectively. The incidence of bronchiolo-alveolar adenomas in the 3200 ppm-exposed groups exceeded the range of historical control data in the Japan Bioassay Research Center. In female rats, the tumor incidences were not increased in any organs of the TCE-exposed groups. In male mice, a significant positive trend with dose was shown for incidences of bronchiolo-alveolar carcinomas, combined incidences of bronchiolo-alveolar adenomas/carcinomas and hepatocellular adenomas. The incidence of Harderian gland adenomas was significantly increased in the 3200 ppm-exposed group, and malignant lymphomas of spleen at this highest dose exceeded the range of historical control data. In female mice, the combined incidence of bronchiolo-alveolar adenomas/carcinomas was significantly increased in the 3200 ppm-exposed group, and the incidences of hepatocellular adenomas and combined incidences of hepatocellular adenomas/carcinomas were significantly increased in the 200, 800 and 3200 ppm-exposed groups with dose dependence except the combined incidence of hepatocellular adenomas/carcinomas in the 200 ppm-exposed group. The incidences of bronchiolo-alveolar adenomas in the 3200 ppm-exposed group and combined incidences of hepatocellular adenomas/carcinomas in the 200 ppm-exposed groups exceeded the ranges of historical control data. Thus, this study provided clear evidence of inhalation carcinogenicity for TCE in both rats and mice.