Effects of chronic high fat diets on renal function and cortical structure in rats.

Four groups (n = 5) of male Wistar rats were fed with different high-fat diets from 21 days to 18-mo-old: soybean oil (SO), canola oil (CA), lard and egg yolk (LE) or CA+LE. Blood lipids, serum creatinine and proteinuria as well as the cortical stereology were analyzed. The cholesterol, HDL-C and triglycerides were highest in CA group. No significant differences were found among the groups to serum creatinine and proteinuria. The BP was highest in LE group and intermediate in CA+LE group. SO and CA groups showed glomeruli most preserved in number and size. Absolute volume of tubuli was greatest in LE group. Renal cortical interstitium was greatest in SO group and smallest in CA group. Cortical vessels showed smallest indices in LE group and greatest ones in CA group; SO and CA+LE groups were intermediate. Chronic administration of different types of dietetic lipid can significantly alter blood biochemistry, BP and renal cortical structure in rats. Considering these features, canola oil was the more beneficial lipid, while lard and egg yolk mixture was the worst lipid. The addition of canola oil in the LE mixture normally was not efficient to alter the renal damage except in the cortical vessels.