Oxidative stress in diabetic patients with retinopathy

Diabetes mellitus (DM) is known to induce oxidative stress along with deranging various metabolisms; one of the late complications of diabetes mellitus is diabetic retinopathy, which is a leading cause of acquired blindness. Poor glycemic control and oxidative stress have been attributed to the development of complications like diabetic retinopathy. The aim of this study was to analyze and correlate oxidative stress marker, Malondialdehyde (MDA), and antioxidants (erythrocyte glutathione, vitamin C) along with glycosylated hemoglobin (HbA1c) and fasting blood sugar (FBS) in diabetic patients with and without retinopathy.

The study population comprised of 50 type 2 diabetics with retinopathy as Group 1 (G1) and 50 type 2 diabetics without retinopathy as Group 2 (G2) in the age group 40-70 years as patients, and 50 age- and gender-matched healthy individuals as controls, Group 3 (G3). FBS, HbA1c MDA, glutathione in erythrocytes, and vitamin C were assayed. Results were analyzed using SPSS 11.0, Mann-Whitney U-test, and Pearson correlation coefficient.

Mean FBS (mg/dl) were 194.04 ± 48.52 (G1), 181.24 ± 50.05 (G2), and 92.20 ± 9.19 (G3) (P < 0.001). Mean values of MDA were 6.65 ± 0.30 (G1), 4.63 ± 0.56 (G2), and 3.90 ± 0.34 (G3) (P < 0.001). The mean reduced glutathione (GSH) levels were (mg/g of Hb) 6.10 ± 1.41 (G1), 6.44 ± 1.53 (G2), and 13.09 ± 2.49 (G3) (P < 0.001). The mean vitamin C levels (mg/dl) were 0.70 ± 0.24 (G1), 0.87 ± 0.29 (G2), and 1.25 ± 0.27 (G3) (P < 0.001).

Estimation of HbA1c, MDA, GSH in erythrocytes, and vitamin C levels can contribute to determine the extent of oxidative stress in diabetes and help in effective control and prevention of the onset and progression of diabetic retinopathy.