Antioxidant status, lipid peroxidation and nitric oxide end products in patients of type 2 diabetes mellitus with nephropathy

OBJECTIVES: Oxidative stress is considered to be a unifying link between diabetes mellitus (DM) and its complications including nephropathy. The aim of the present study was to evaluate oxidative stress status in Asian Indian patients of type 2 DM with nephropathy. DESIGN AND METHODS: Serum levels of malondialdehyde (MDA) and nitric oxide end products (nitrite and nitrate), activities of erythrocyte superoxide dismutase (SOD), catalase (CAT) and reduced glutathione (GSH) content were estimated in controls, patients of type 2 DM without nephropathy (group 1) and with nephropathy (group 2). RESULTS: Serum MDA concentration was significantly high in both the groups of diabetic patients as compared to controls, (p < 0.05), with group 2 having a significantly higher value than group 1 (p < 0.05). Significantly elevated serum nitrite levels were found in diabetic patients as compared to controls (p < 0.001), however, no significant difference was found between group 1 and group 2. Moreover, serum nitrate as well as nitrite + nitrate levels were significantly higher in group 2 as compared to controls (p < 0.05). Activity of erythrocyte SOD and CAT was significantly reduced in both groups as compared to controls (p < 0.001) with catalase activity in group 2 being significantly lower than group 1 (p < 0.05). Erythrocyte GSH content was significantly lower in group 2 as compared to controls (p < 0.05) and group 1 (p < 0.05). CONCLUSIONS: Results of the present study indicate that oxidative stress is increased and antioxidant defenses are compromised in type 2 DM. These derangements are of a higher magnitude in patients of type 2 DM with nephropathy.