黄芪多糖对肥胖模型大鼠胰岛素抵抗的作用研究

Study of Efficacy of Astragalus Polysaccharides on Insulin resistance in Obesity Model Rats

目的:观察黄芪多糖对高脂饲料诱导肥胖大鼠的影响,探讨黄芪多糖改善胰岛素抵抗的作用机制,为其应用于临床提供理论依据。方法:采用高脂饲料连续喂养6周的方法复制大鼠肥胖模型,将其分为模型组、黄芪多糖组(400 mg·kg^(-1))、吡格列酮组(20 mg·kg^(-1)),另设空白组,各组给予相应的药物灌胃,连续给药4周。检测血清中空腹血糖(fasting blood glucose,FBG)、三酰甘油(triglyceride,TG)、胆固醇(total cholesterol,TC)、胰岛素(insulin,INS)水平,计算胰岛素敏感指数(ISI)、内脏脂肪含量(VF/W);PCR法检测大鼠骨骼肌磷脂酰肌醇3激酶(PI3K)mRNA表达;Western Blot法检测大鼠骨骼肌PI3K p85蛋白的表达。结果:黄芪多糖组及吡格列酮组TG、TC、INS、VF/W水平明显降低(P<0.05),ISI水平升高(P<0.05),PI3KmRNA表达水平明显升高(P<0.05),PI3Kp85α的蛋白表达明显降低(P<0.05)。结论:黄芪多糖改善肥胖大鼠胰岛素抵抗可能是通过降低血清中TC、TG及上调骨骼肌中PI3K来实现的。

Objective:To observe the efficacy of astragalus polysaccharides on obesity rats induced by high-fat diet,and to explore the mechanism of astragalus polysaccharides in improving insulin resistance,so as to provide theoretical basis for its clinical application.Methods:The rat obesity models were established by feeding high fat diet for 6 weeks.Then they were divided into the model group,astragalus polysaccharide group(400 mg·kg^(-1)),pioglitazone group(20 mg·kg^(-1)),and the blank group.Each group was given corresponding drugs by gavage for 4 weeks.Fasting blood glucose(FBG),triglyceride(TG),total cholesterol(TC)and insulin(INS)in serum were detected,and insulin sensitivity index(ISI)and visceral fat content(VF/W)were calculated.The mRNA expression of phosphatidylinositol 3 kinase(PI3K)was detected by PCR and the protein expression of PI3K was detected by Western Blot.Results:The levels of TG,TC,INS and VF/W in astragalus polysaccharide group and pioglitazone group were significantly decreased(P<0.05),ISI level was increased(P<0.05).PI3Kp85αprotein expression was significantly decreased(P<0.05),while the PI3KmRNA expression level was significantly increased(P<0.05).Conclusion:Astragalus polysaccharides can improve insulin resistance in obese rats by reducing serum cholesterol,triglyceride and up-regulating PI3K in skeletal muscles.