RESUMO
Purpose: To investigate the role of oxidative stress in the development of diabetic retinopathy. The serum malondialdehyde [MDA] as an index of lipid peroxidation, the erythrocyte glutathione peroxidase [GPX] and superoxide dismutase [SOD] activity, were measured in 15 healthy control subjects and 30 diabetic patients [15 without retinopathy and 15 with diabetic retinopathy]. Serum MDA levels, erythrocytes GPX and SOD activity were estimated by specific colourimetric assays. Serum MDA levels were significantly elevated in diabetic patients compared with those in control subjects. Significant reduction in the activity of GPX was detected in diabetic patients when compared with control subjects. Patients with diabetic retinopathy showed a significant higher MDA level and lower GPX activity when compared with diabetics without retinopathy. Significant reduction in SOD activity was detected only in diabetic patients with retinopathy when compared with control subjects. Free radicals formation in diabetes mellitus which increases over time may play a role in the development of diabetic retinopathy, which is an important complication of the disease