||Bio-Research Laboratories, Ltd., Montreal, Quebec. ;Dow Chemical Co., Midland, MI.;Environmental Protection Agency, Washington, DC. Office of Toxic Substances.
Albino rats were exposed seven hours a day for up to twenty days to 0.5, 5.0 or 10 ppm trimethoxysilane. A control group was treated in all respects similarly to the experimental groups except that these rats were not exposed to the test article. All of the high dose rats and four of ten rats in the 5.0 ppm dose group died or were sacrificed in the course of the study. Prior to death, these animals exhibited general weakness, a reduction in food consumption and body weight, lung congestion, nasal discharge, and associated perinasal staining. None of the low dose animals or the air controls revealed similar findings. Blood biochemical and urinary parameters were normal in the 5.0 and 0.5 ppm dose groups. The high mortality rate in the 10.0 ppm dose group precluded a complete analysis. Hematological evaluation indicated a dose-dependent increase in RBC, hematocrit and hemoglobin values, a dose-dependent decrease in total white blood cells and a 'shift to the left' in the differential WRC count. These findings were observed only in the high and intermediate dose groups and correlated well with the general dehydrated condition of these animals and the reversal of the myeloid-erythroid ratio in these groups. Gross pathological examination of the high and intermediate dose groups revealed areas of focal reddening and atelectasis in the lungs to collapse when removed from the thoracic cavity.