Background: Diabetes mellitus is a metabolic disorder characterized by increased production of free radicals and oxidative stress. The aim of this study was to evaluate the activity of antioxidant enzymes, superoxide dismutase (SOD), glutathione reductase (GR), and glutathione peroxide (GSH-PX) in type 2 diabetic patients compared with healthy subjects.
Methods: This cross-sectional study was conducted on 100 type 2 diabetic patients and 100 healthy controls. Total antioxidant capacity and fasting serum levels of SOD, GR, and GSH-Px were measured. All data were analyzed using SPSS software compatible with Microsoft Windows.
Results: The activity levels of SOD were lower in diabetic patients (111.93 ± 354.99 U/g Hb) than in healthy controls (1158.53 ± 381.21 U/g Hb), but this was not significant. Activity levels of GSH-PX and GR in diabetics (62.33 ± 36.29 and 7.17 ± 5.51 U/g Hb, respectively) were higher than in controls (24.62 ± 11.2 and 3.16 ± 2.95 U/g Hb, respectively). The statistical difference in enzyme activity of both GSH-Px and GR was significant (P <0.05).
Conclusion: The increasing production of free radicals and changes in activity levels of antioxidant enzymes in order to scavenge free radicals and/or the effect of diabetes on the activity levels of antioxidant enzymes has an important effect on diabetic complications and insulin resistance. Evaluation of the levels of antioxidant enzymes and antioxidant factors in patients at different stages of the disease, and pharmaceutical and nutritional interventions, can be helpful in reducing oxidative stress in type 2 diabetic patients. There were positive relationship between BMI and the activity of antioxidant enzymes including SOD, GR and GPX in both groups.