黄芪多糖对糖尿病心肌病大鼠AMPK-mTOR通路的调控机制研究

Regulation Mechanism of Astragalus Polysaccharides on Diabetic Cardiomyopathy Rats by AMPK-mTOR Pathway

目的:研究黄芪多糖对糖尿病心肌病(DCM)大鼠的干预作用,阐明黄芪多糖对糖尿病心肌病大鼠心肌AMPK-mTOR信号通路的影响,探讨黄芪多糖对糖尿病心肌病大鼠心肌的保护作用。方法:80只健康雄性SD大鼠,随机选取10只作为对照组,其余70只采用高糖高脂饮食联合链脲佐菌素腹腔注射复制DCM模型。将模型复制成功的大鼠随机分为模型组、黄芪多糖组、氯喹组、黄芪多糖+氯喹组。连续给药8周后,超声心动图评价大鼠的心脏功能,HE染色观察心肌组织的病理变化,Masson染色检测大鼠心肌纤维化程度,蛋白质印迹法测定心肌组织中AMP活化蛋白激酶(AMPK)、p-AMPK、哺乳动物雷帕霉素靶蛋白(mTOR)、p-mTOR蛋白的表达,实时PCR检测心肌组织AMPK、mTOR mRNA的表达情况。结果:与对照组比较,模型组大鼠左室收缩末内径(LVESD)、左室舒张末内径(LVEDD)、mTOR蛋白、p-mTOR蛋白、mTOR mRNA明显升高,左心室射血分数(LVEF)、左心室短轴缩短率(LVFS)、AMPK、p-AMPK、AMPK mRNA明显降低(均P<0.01)。与模型组比较,黄芪多糖组组LVEDD、LVESD、mTOR蛋白、p-mTOR蛋白明显降低,LVEF、LVFS、AMPK蛋白、p-AMPK蛋白明显升高(均P<0.01)。与黄芪多糖组比较,黄芪多糖组+CQ组大鼠心肌p-AMPK蛋白、AMPK mRNA水平明显降低,mTOR、p-mTOR、mTOR mRNA水平明显升高(P<0.05,P<0.01)。结论:黄芪多糖能调节AMPK-mTOR信号通路上相关蛋白及的mRNA表达,激活AMPK-mTOR信号通路,进而发挥对糖尿病心肌病的保护作用。

Objective:To study the effect of astragalus polysaccharides(APS)on diabetic cardiomyopathy(DCM)rats,clarify the effect of APS on AMPK-mTOR signaling pathway in DCM rats,and explore the protective effect of APS on DCM rats.Methods:A total of 80 healthy male SD rats were selected.Ten of the rats were randomly divided into a control group.The other 70 rats were fed with high-sugar and high-fat diet,and intraperitoneally injected streptozotocin(STZ)to induce and duplicate DCM model.The rats with DCM model were randomly divided into a model group,an APS group,a chloroquine group,and an APS+chloroquine group.After treatment for 8 weeks,echocardiography was used to evaluate the cardiac function of rats,and hematoxylin-eosin(HE)staining was used to observe the pathological changes of myocardial tissue.Masson staining was used to detect the degree of myocardial fibrosis,and Western blot was used to detect the protein expressions of adenosine 5′-monophosphate-activated protein kinase(AMPK),phosphorylated-AMPK(p-AMPK),mammalian target of rapamycin(mTOR),and phosphorylated-mTOR(p-mTOR),and real-time quantitative polymerase chain reaction(real-time PCR)was used to detect the messenger ribonucleic acid(mRNA)expressions of AMPK and mTOR.Results:Compared to the control group,left ventricular end diastolic dimension(LVEDD),left ventricular end systolic diameter(LVESD),proteins of mTOR and p-mTOR,and mRNA of mTOR in the model group were significantly increased,while left ventricular ejective fraction(LVEF),left ventricular fraction shortening(LVFS),proteins of AMPK and p-AMPK,and mRNA of AMPK were significantly decreased(P<0.01).Compared with the model group,LVEDD,LVESD,proteins of mTOR and p-mTOR in the APS group were significantly decreased,while LVEF,LVFS,proteins of AMPK and p-AMPK were significantly increased(P<0.01).Compared with the APS group,protein of p-AMPK and mRNA of AMPK in the APS+chloroquine group were significantly decreased,while proteins of mTOR,p-mTOR and mRNA of mTOR were significantly increased(P<0.05,P<0.01).Conclusion:APS regulated the expression of related proteins and mRNA in AMPK-mTOR signaling pathway,and activated AMPK-mTOR signaling pathway,thus playing a protective role in DCM.