The Effect Of Oxidative Stress On The Pancreatic β-Cell Function And It's Mechanism In Type 2 Diabetes Mellitus Patiens

objective: To investigate the relationgship between the level of oxidative stress and the first-phase of pancreatic beta cell insulin secretion in subjects with different glucose tolerances .Methods: Forty patients with newly diagnosed type 2 diabetes mellitus (DM group), thirty-seven patients with Impaired glucose tolerance (IGT group), forty-three subjects with normal glucose tolerance (NGT group) underwent intravenous glucose tolerance test (IVGTT).Fasting adiponectin (APN) and 8-hydroxydeoxyguanosin (8-OHdG) was assayed by ELISA.Malondialdehyde (MDA) and activity of superoxide dismutase (SOD) were measured by colorimetry.Insulin area under the curve (AUC) from 0 min to 10 min ,AIR3-5, homeostasis model assessment for insulin resistance(HOMA-IR) and forβ-cell function (HOMA-β) were calculated.The relationship between oxidative stress and adiponectin,AUC,AIR3-5, HOMA-IR,HOMA-βwas explored.Results: (1) The levels of 8-OHdG,MDA,LDL-C and TG in IGT group and DM group were significantly higher than those in NGT group(P <0.05).(2) The levels of adiponectin,SOD,AUC and AIR3-5 in IGT group and DM group were significantly lower than those in NGT group(P<0.05).(3) The levels of 8-OHdG ,MDA,LDL-C and TG in DM group were significantly higher than those in IGT group (P <0.05),and adiponectin,SOD ,AUC and AIR3-5 in DM group were significantly lower than those in IGT group (P <0.05).(4) MDA and 8-OHdG were positively correlated with HOMA-IR, TG,FPG,LDL-C and negatively correlated with adiponectin,HOMA-β,AUC,AIR3-5 ,SOD was positively correlated with adiponectin,HOMA-β,AUC,AIR3-5 and negatively correlated with FPG,TG,LDL-C,HOMA-IR.(5) Adiponectin was positively correlated with HDL-C, HOMA-β,AUC,AIR3-5 and negatively correlated with TG, LDL-C, FPG.(6) Multiple regression stepwise analysis showed that 8-OHdG and SOD was the independent factor of AIR3-5 (the Beta value was -0.488,0.426 respectively ) (R2=0.675,F=113.07,P<0.01).Conclusion: Type 2 diabetes have obvious glucolipotoxicity and hypoadiponectinemia, and oxidative stress had a significant effect on the first phase of pancreaticβcell insulin secretion,which may contribute to the pathogenesis of type 2 diabetes.