Evaluation of the effect of oxidative stress and vitamin E supplementation on renal function in rats with streptozotocin-induced Type 1 diabetes

We investigated the possible role of reactive oxygen species (ROS) on renal function in experimental diabetes.Materials and MethodsSeven groups of male rats were studied. Group I consisted of control animals. Diabetes was induced (by streptozotocin) in the animals in the other groups and they received either insulin or vitamin E (300 or 600 mg/kg), both insulin and vitamin E, or no treatment for 4 weeks. At the end of the study, blood pressure was measured and parameters of kidney function and oxidative stress were evaluated in serum and kidney tissue samples.ResultsDiabetic animals had higher blood pressures; increased serum glucose, urea, creatinine, cyclic guanosine monophosphate (cGMP); increased kidney tissue levels of malondialdehyde and inducible nitric oxide synthetase (iNOS); and reduced serum glutathione peroxidase when compared with control animals. Blood glucose levels in diabetic animals were controlled by insulin and not by any dose of vitamin E alone. However, all other measured parameters improved towards control levels with either insulin or vitamin E in either dose. An additive beneficial effect was observed on the levels of iNOS and cGMP when both forms of treatment were used in diabetic animals.ConclusionsWe conclude that ROS may play an important role in diabetes-induced nephropathy in this rat model. Vitamin E supplementation in addition to insulin can have additive protective effects against deterioration of renal function in this model.