Background & Objective: Diabetic hyperglycemia is associated with increased production of Reactive Oxygen Species (ROS). ROS reacts with DNA results in products such as 8-hydroxydeoxyguanosine that excrete in urine due to DNA repair processes. This study aims to evaluate correlation between oxidative damage of DNA and protein glycation in patients with Type 1 diabetes. We measured urinary 8-OHdG level in diabetic and control group and evaluated its correlation to glycated hemoglobin (HbA1c) and glycated serum protein (GSP) levels. Furthermore plasma malondialdehyde (MDA) level was measured as an important indicator of lipid peroxidation in diabetes.

Materials & Methods: We studied 32 patients with diabetes mellitus Type 1 and compared them with 48 sex and age-matched non-diabetic controls. GSP and MDA measurement were made by colorimetric assay. Hemoglobin A1c measured by ion-exchange chromatography method and urinary 8-OHdG measurement was made by competitive in vitro enzyme-linked immunosorbent assay (ELISA).

Results: In the present study urinary 8-OHdG, blood HbA1c, plasma MDA and GSP levels were significantly higher in diabetics comparing to the control subjects (P<0.05). Furthermore, we found significant correlation between urinary 8-OHdG and HbA1c (P<0.05) in diabetic group. In addition, fasting blood sugar showed significant correlation with GSP and MDA (P<0.05). However the correlation of MDA with HbA1c was not significant in diabetic patients.

Conclusion: This case-control study in young diabetic patients showed that increased blood glucose and related metabolic disorders result in oxidative stress and oxidative damage to DNA and lipids. Furthermore oxidative damage to DNA correlated to glycemic control, while there was no significant correlation between lipid peroxidation and the level of HbA1c.