Altered serum levels of melatonin, antioxidant enzymes and oxidative stress in individuals with diabetes mellitus Type 2

Abstract

Background and aim: Dysregulation of melatonin, is thought to play a role in the development of type 2 diabetes mellitus. The objective of this study was to evaluate the relationship between circulating melatonin, lipid peroxide, total antioxidant capacity (TAC), nitric oxide (NO), superoxide dismutase (SOD) concentrations in adults with and without type 2 diabetes mellitus. Included in the study were 46 patients, newly diagnosed with type 2 diabetes mellitus and 46 healthy control subjects. The patients and control subjects were asked to come to the clinic in the morning, after an 8-hour fast. At that time, 5 mL of venous blood was collected, to determine biochemical indicators. Melatonin level was assessed by ELISA technique. Results: In T2DM subjects, mean values of serum melatonin, NO, TAC, and lipid peroxide were found to be significantly decreased compared to the control group (39±4.7versus 100.9±26.5pg/ml)), (26.67±3.18 versus 34.2±3.2µmoles/L), (188.5±27.3 versus 263±32.62µmol/mg of protein), and (3.32±2.62 versus 6.1± 2.68nmole/mL) respectively. Whereas serum fasting blood glucose (FBG), and SOD level was increased in the diabetic groups compared to the control group (181±22.9 versus 101±3.8 mg/dL) (5.79±2.03U/mL, versus 3.68±1.53 U/mL), respectively. Conclusions: Our study supports the hypothesis that abnormal production of oxidative stress markers, NO, and melatonin can contribute to the pathogenesis of T2DM.