Comparative analysis of the renoprotective effects of pentoxifylline and vitamin E on streptozotocin-induced diabetes mellitus

Background: Oxidative stress (OxS) induced by diabetes plays an important role in the development of diabetic nephropathy. Studies have shown that antioxidants are beneficial in its reduction. Vitamin E has been documented as providing the most improvement in the antioxidative status. Recently, pentoxifylline (PTX) has been proposed to have antioxidant properties. Aim: The aim of the study was to assess the ability of two antioxidants to reduce lipid peroxidation and renal hypertrophy in vivo. Methods: Diabetes was induced by streptozotocin (STZ) in rats. Treatment groups were divided as follows: healthy (H), diabetic without treatment (STZ), PTX treated group (STZ + PTX), and vitamin E supplemented (STZ + E) group. At 8 weeks, kidneys were removed; one was homogenized to quantify lipoperoxide levels (LPOS), and the other was used to study the morphological changes by electron microscopy (EM). Additionally, plasma total antioxidant activity (TAA) was quantified. Results: A reduction in LPOS was observed in both groups: PTX and vitamin E with regard to STZ group. PTX increased TAA compared to STZ + E, which restored it to its normal values. However, both treatments reduced the LPO/TAA ratio to lower basal levels; hence, similar results were obtained in terms of correcting functional parameters. Structural changes in STZ rats included a glomerular membrane thickening, podocyte flattening, as well as loss of fenestration in the endothelial layer. All these changes were less aggressive for treated rats. Conclusions: Vitamin E and PTX have potential therapeutic properties that may help to retard the rate of deterioration of diabetic kidneys.