黄芪多糖对2型糖尿病大鼠肝脏AMPK苏氨酸磷酸化的影响

目的:观察2型糖尿病(T2DM)大鼠肝脏组织中腺苷酸活化蛋白激酶(AMPK)磷酸化表达的变化,并探讨黄芪多糖(APS)对T2DM的治疗作用及可能机制。方法:雄性SPF级SD大鼠,随机分为4组:正常对照组(C组,n=8)和APS对照组(APS组,n=8),以普通饲料喂养;T2DM组和T2DM+APS治疗组(T2DM+APS组),以高脂饲料喂养。第8周末,行尾静脉一次性注射小剂量链脲佐菌素(STZ,25mg/kg),实验期间定期检测动物随机血糖(BG)、空腹血糖(FBG)、口服糖耐量(OGTT)、血胰岛素(FINS),计算胰岛素敏感指数(ISI)。于APS治疗第8周末,取各组动物的肝脏组织,以Western blotting检测AMPK磷酸化水平。结果:T2DM组出现高血糖、糖耐量降低,经APS治疗8周后,T2DM+APS组各项实验指标均有显著性改变,肝脏组织中磷酸化AMPK水平较T2DM组显著上升(P<0.01)。结论:APS可以显著改善T2DM大鼠胰岛素抵抗,其作用机制可能与APS增加磷酸化AMPK表达水平,进而改善其能量代谢途径有关。

Effect of APS on the Expression of Phosphyorylation of AMPK in Liver Tissue of Type 2 Diabetic Rat

Objective:To investigate the expression of the phosphorylation of AMP-activated protein kinase(AMPK) in liver of type 2 diabetic rats,and explore the effect of Astragalus polysaccharide(APS) on the treatment of T2DM.Method:Male SD rats(SPF) were randomly divided into four groups:control group(C,n=8),APS control group(APS,n=8),which were fed with normal food;diabetic rats group(T2DM,n=8) and APS treated group(T2DM +APS,n=8) which were established by high fat feeding with small dosage STZ injection(25mg/kg).Blood glucose,oral glucose tolerance test,plasma insulin concentration and insulin sensitivity index were periodically observed.At the end of 8-week treatment with APS,the expression of the total AMPK and pAMPK in the liver were assessed by western blotting.Results:The rats of T2DM were characterized with hyperglycemia,and impaired oral glucose tolerance.After treatment with APS for 8 weeks,there were significant distinction on every detected index and a striking increase in the expression of the threonine phosphorylation of AMPK in group T2DM+APS compared to group T2DM(P<0.01).There was no obvious changes between group C and APS(P>0.05).Conclusion:After treatment with APS,there was a significant amelioration on insulin resistance in diabetic rats.The potential mechanisms of APS effected on diabetic rats may involve in the following pathway:promoting the expression of pAMPK and improving the energy metabolic pathway of the livers in type 2 diabetic rats.