The investigation of the oxidative stress-related parameters in type 2 diabetes mellitus.

OBJECTIVE: Oxidative stress, defined as an imbalance between reactive oxygen species production and breakdown by endogenous antioxidants, is closely associated with diabetes mellitus. The diabetes is characterized by hyperglycemia together with biochemical alterations of glucose and lipid peroxidation. Oxidative stress has been implicated in the pathogenesis of type 2 diabetes and its complications.

METHODS: This study was conducted to investigate the variation in oxidative stress-related parameters in type 2 diabetes. Blood serum samples were collected from diabetes patients and nondiabetes healthy controls. Glucose concentrations, levels of glycated hemoglobin (A1C) and serum oxidative stress markers (glucose-6-phosphate dehydrogenase [G6PDH], malondialdehyde [MDA], glutathione [GSH], glutathione reductase [GR], glutathione peroxidase [GPx] and superoxide dismutase [SOD]) were estimated.

RESULTS: Fasting serum glucose concentration in type 2 diabetes patients of both sexes was increased significantly as compared with the healthy controls. Level of A1C was greater than standards. Significant elevation in MDA level and depletion in GSH content were observed in diabetes patients in comparison with controls. The diminution in G6PDH activity was accompanied in part by a decrease in the antioxidative enzymes activities (GPx and GR), and in part by an increase in SOD activity in all diabetes patients as compared with the control group. The regression analysis showed no correlation between diabetes duration and severity of oxidative stress; however, there was a significant association between A1C and severity of oxidative stress.

CONCLUSIONS: The present study shows that there is an oxidative stress state in type 2 diabetes patients compared with healthy subjects. Our data suggest that chronic hyperglycemia causes a significant change in oxidative stress markers.