Acute urinary tract toxicity of tetraethylorthosilicate in rats.

Acute stomach, kidney, and bladder toxicity was evaluated in F344 rats after gastric gavage of tetraethylorthosilicate (TES) at daily doses of 0, 0.111, 0.223, and 0.333 g. Five rats of each sex at each dose were sacrificed after 1, 2, and 4 days. In TES-treated groups, silicate accumulated in the stomach glands and the muscle layer of the forestomach and glandular stomach. Serum chemistries demonstrated acute onset of renal failure. In the kidneys, acute tubular necrosis, accumulation of silicates, and superficial necrotizing papillitis were observed. In the renal pelvis and bladder, there was urothelial simple hyperplasia, focal erosion of the mucosa, edema, and inflammation. These acute toxic changes were dose and time dependent, but significant sex differences were not observed. The microscopic changes in the urothelium were similar to those observed following administration of high doses of sodium saccharin to male rats in which urinary silicate precipitate and crystals form.