抗纤益心方通过AMPK/mTOR通路改善扩张型心肌病大鼠心功能的作用机制

Kangxian Yixin Formula improved cardiac function in rats with dilated cardiomyopathy via AMPK/mTOR pathway

目的探讨抗纤益心方通过腺苷酸活化蛋白激酶(AMPK)/哺乳动物雷帕霉素靶蛋白(mTOR)信号通路对扩张型心肌病(DCM)大鼠心肌细胞自噬、心功能的影响及其机制。方法将60只Wistar大鼠随机分为正常组,模型组,抗纤益心方高、低剂量组和卡托普利组,每组各12只。模型组、抗纤益心方组和卡托普利组经呋喃唑酮水溶液诱导扩张型心肌病模型,药物治疗8周。超声心动仪检测各组大鼠心脏左室收缩末期内径(LVESD)、左室舒张末期内径(LVEDD)、缩短分数(FS)、左室射血分数(LVEF)的变化;HE染色观察心肌细胞排列及形态;透射电镜观察线粒体超微结构及自噬;Western blot检测自噬相关蛋白微管相关蛋白1轻链3(LC3)、Beclin1、p62与AMPK、mTOR表达及其磷酸化水平。结果与正常组比较,模型组LVESD和LVEDD增加,FS和EF降低;与模型组比较,抗纤益心方高剂量组和卡托普利组LVESD和LVEDD降低,FS和EF增加;模型组心肌细胞线粒体排列紊乱,局部肌丝断裂,线粒体肿胀伴空泡样变化,边界模糊不清,抗纤益心方高剂量治疗后线粒体超微结构的损伤改善;与正常组比较,模型组心肌LC3-II/LC3-I、Beclin1蛋白表达降低、p62表达升高;与模型组比较,抗纤益心方高剂量组和卡托普利组LC3-II/LC3-I、Beclin1蛋白表达增加,p62表达降低;与正常组比较,模型组p-AMPK/AMPK降低,p-mTOR/mTOR升高;与模型组相比,抗纤益心方高剂量组和卡托普利组p-AMPK/AMPK升高,p-mTOR/mTOR降低。结论抗纤益心方通过促进扩张型心肌病大鼠心肌细胞自噬,改善心脏功能,其作用机制可能与调控AMPK/mTOR通路有关。

Objective To investigate the effect of Kangxian Yixin Formula(KXYXF) on cardiac function and adenosine 5‘-monophosphate-activated protein kinase(AMPK)/mammalian target of rapamycin(mTOR) pathway of cardiomyocytes in rats with dilated cardiomyopathy(DCM). Methods 60 Wistar rats were randomly divided into normal group, model group, KXYXF group and captopril group. Rat DCM model was established by administering furazolidone solution. After 8-week intervention, the changes of left ventricular end systolic diameter(LVESD), left ventricular end diastolic diameter(LVEDd), fraction shortening(FS), left ventricular ejection fraction(LVEF) were measured by using echocardiography;the pathological changes of heart tissue were evaluated with HE staining;autophagy related proteins LC3, Beclin1, p62, AMPK, mTOR and their phosphorylation levels were detected by using Western blot assay. Results Compared with the normal group, LVESD and LVED increased while FS and EF decreased in the DCM model group. Compared with the model group, the rats in the KXYXF and captopril group had decreased LVESD and LVED, and increased FS and EF. The expression of LC3-II/LC3-I and Beclin1 protein in the model group was lower than that in the normal group, and p62 protein expression was higher. The expression of LC3-II/LC3-I and Beclin1 protein in the KXYXF group and captopril group was higher than those in the model group, and p62 protein expression was lower. Compared with the normal group, the p-AMPK/AMPK ratio of myocardial tissue in the model group was reduced, and the p-mTOR/mTOR ratio was increased;compared with the model group, the p-AMPK/AMPK ratio of myocardial tissue in the KXYXF group and the captopril group was increased, and the p-mTOR/mTOR ratio was reduced. Conclusion KXYXF could promote autophagy of cardiomyocytes and improve cardiac function in DCM rats, and its mechanism may be related to AMPK/mTOR pathway.