Oxidative stress induced by hyper-glycemia in diabetes mellitus is a ma­jor cause for development and pro­gression of diabetic microvascular complications such as nephropathy. Thus, the protective action of trimeta-zidine "TMZ" against oxidative stress was investigated in a rat model of dia­betic nephropathy. Diabetes was in­duced in male Sprague -Dawley rats using streptozotocin (65 mg/kg). Ei­ther TMZ (10 mg/kg) or captopril (50 mg/kg) was gavaged daily for 12 weeks. After the end of the experi­mental period, renal functions and re­nal oxidative stress markers were as­sessed. Either captopril or TMZ exhibited significant improvement of the renal function that was correlated with significant decrease in the renal
oxidative stress markers. In conclu­sion, the antioxidant property of TMZ may offer a potential therapeutic source for the treatment of diabetic nephropathy.