Acute Urinary Tract Toxicity of Tetraethylorthosilicate in Rats

Acute stomach, kidney, and bladder toxicity was evaluated inF344 rats after gastric gavage of tetraethylorthosilicate (TES)at daily doses of 0, 0.111, 0.223, and 0.333 g. Five rats ofeach sex at each dose were sacrificed after 1, 2, and 4 days.In TES-treated groups, silicate accumulated in the stomach glandsand 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 therenal pelvis and bladder, there was urothelial simple hyperplasia,focal erosion of the mucosa, edema, and inflammation. Theseacute toxic changes were dose and time dependent, but significantsex differences were not observed. The microscopic changes inthe urothelium were similar to those observed following administrationof high doses of sodium saccharin to male rats in which urinarysilicate precipitate and crystals form.