The cytotoxic effects of trimethylpentane on rat renal tissue.

The primary objective of the investigation was to determine the acute cytopathologic effects of 2,3,4-trimethylpentane, a major constituent of gasoline, on renal tissue of the mature male rat. Three groups of 9 Fischer-344 rats each were administered trimethylpentane by gavage twice weekly for 7, 14, or 28 days at a concentration of 1.5 ml/kg body weight. The tissues were fixed by perfusion, and subsequently processed for scanning and transmission electron microscopy. Although the manifestations of hydrocarbon toxicity were evident in all experimental tissues examined, the extent and magnitude of cellular lesions increased as the exposure period progressed. The only structural change detected within the glomerular complex was a significant increase in the number of microvilli associated with various branches of the podocytes. Cells of the proximal convoluted tubule were characterized by the presence of membrane-bound, PAS positive hyaline droplets. At focal points along segments P1 and P2 of the proximal tubule intact epithelial cells dissociated from the basal lamina, underwent necrosis, and subsequently collected along the length of the tubular lumen. The cellular debris concentrated at the corticomedullary junction. Tubules at the site were dilated focally and the epithelial lining was attenuated. Results of the study indicate that the manifestations of trimethylpentane toxicity among renal cells are associated with the proliferation of hyaline droplets.