Peroxisomal proliferation in rat kidney induced with DEHP I. Numerical change by light microscopic morphometry.

Abstract

Effects of DEHP (di-2-ethylhexyl phthalate) were studied on renal tubular epithelial cells of rats. The 1%, 2% and 4% (w/w) DEHP administered and control rats were sacrificed at 1, 2 and 4 weeks. The tissues were incubated in alkaline DAB medium and embedded in Epon. The 0.5μm thick sections were observed by light microscopy with an ocular micrometer. The number of peroxisomes was determined for the transected area per 25μm² in 40 different tubular cytoplasms. The differences in the number of peroxisomes between the experimental and control groups were evaluated from the viewpoint of various responses depending on the duration of administration, dose of DEHP, parts off the nephron and sex. Peroxisomal proliferation in DEHP-treated rats occured at low levels of dosage in a short time. The differences in increase between straight parts and convoluted parts of proximal tubules became the most obvious over a long time. The difference depending on sex was not so apparent. The response of proximal tubular epithelial cells to DEHP is not similar to that induced in liver cells by the same drug. Peroxisomes in renal tubular epithelial cells may play a role in lipid metabolism to a lesser extent than those in liver cells.