© 1995 Oxford University Press
research-article |
Subchronic Inhalation Toxicity of 1,1,1,3-Tetrachloropropane in Rats
*Dow Corning Corporation Corporation, 2200 West Salzburg Road, Midland, Michigan 48686
Received March 4, 1994; accepted September 2, 1994
The purpose of this study was to evaluate the inhalation toxicity of 1,1,1,3-tetrachloropropane (TCP), an intermediate in production of chlorinated silicone fluids. Male and female Sprague- Dawley rats were exposed 6 hr/day, 5 days/week, for days to TCP at concentrations of 0, 25, 75, or 225 ppm (Phase study) and to 0, 1, 5, or 10 ppm (Phase II study). Phase II of study was conducted because a no-observed-effect level was not achieved in Phase I. No animals died during the study. Clinical signs of toxicity included oral, nasal, and/or ocular discharge. No statistically significant differences were observed in either body weights or food consumption between exposed and control animals. Clinical pathology did not indicate any treatment related effects. Absolute and relative liver and kidney weights were increased in male and female rats exposed to 225 ppm TCP, and heart weights were increased in male rats exposed to 225 ppm TCP. The liver and heart weight changes were supported by the findings of microscopic lesions in these organs. These lesions consisted of multifocal/focal myofiber degeneration necrosis with adjacent chronic myocarditis in the heart and multifocal single-cell necrosis in the liver parenchyma. The liver lesions had essentially resolved at the end of a 28-day recovery period but the heart lesions were still present in male rats in the recovery group exposed to 225 ppm TCP. No treatment-related effects were observed in animals exposed to 1, 5, or 10 ppm TCP. The data of this study showed that the no-observable-effect level for TCP was 10 ppm in male and female CD rats.