辣木叶乙醇提取物通过AMPK信号通路介导的自噬对小鼠急性心肌梗死的保护作用

Protection Effect of Ethanol Extract of Moringa Oleifera on Acute Myocardial Infarction in Mice by A utophagy Mediated by AMPK Signaling Pathways

目的分析辣木叶乙醇提取物(EE-MO)通过AMP活化蛋白激酶(AMPK)信号通路介导的自噬对小鼠急性心肌梗死(AMI)的保护作用。方法制备小鼠AMI模型,将90只小鼠随机分成假手术组、模型组、EE-MO低、中、高剂量组和氯吡格雷(CD)组,每组15只,造模成功后灌胃给药,连续4周。TTC染色法计算心肌梗死面积。HE染色法观察心肌组织病理损伤并评分。超声心动图分析心功能指标。生化仪检测血清心肌酶含量。Westernblot检测自噬和AMPK/雷帕霉素靶蛋白(mTOR)信号通路相关蛋白。结果EE-MO中、高剂量组和CD组心肌梗死面积低于模型组(均P<0.05)。模型组血清肌酸激酶(CK)、肌酸激酶同工酶(CK-MB)和肌红蛋白(Mb)水平高于假手术组(均P<0.05);EE-MO中、高剂量组和CD组血清CK、CK-MB和Mb水平低于模型组(均P<0.05)。与假手术组相比,模型组左心室短轴缩短率(LVFS)和射血分数(LVEF)水平降低,舒张末内径(LVEDd)和收缩末内径(LVESd)水平升高(均P<0.05);与模型组相比,EE-MO中、高剂量组和CD组LVFS和LVEF水平升高,LVEDd和LVESd水平降低(均P<0.05)。EE-MO改善心肌组织病理损伤,降低心肌损伤评分(均P<0.05)。与假手术组相比,模型组心肌组织中Beclin1蛋白、LC3Ⅱ/LC3Ⅰ水平升高,p62、p-AMPK/AMPK和p-mTOR/mTOR水平降低(均P<0.05);与模型组相比,EEMO中、高剂量组和CD组心肌组织中Beclin1、LC3Ⅱ/LC3Ⅰ水平下降,p62、p-AMPK/AMPK和p-mTOR/mTOR水平升高(均P<0.05)。结论EE-MO可能通过AMPK信号通路介导的自噬实现保护心肌组织的作用。

Objective To analyze the protective effect of ethanol extract of Moringa olei fera(EE-MO)on acute myocardial infarction(AMI)in mice by autophagy mediated by AMP-activated protein kinase(AMPK)signaling pathways.Methods The models of AMI mice were prepared,and 90 mice were randomly divided into sham operation group,model group,lo w-dose,me-dium-dose and high-dose EE-MO groups,and clopidogrel CD)group(n=15 in each group).After successful modeling,intragas-tric administra tion was conducted for 4 weeks.The area of myocardial infarction was calculated by TTC staining.The pathologi-cal damage of myocardial tissues was observed and scored by HE staining.The cardiac function indexes were analyzed by echo-cardiography.The contents of serum myocardial enzymes were detected by biochemical analyzer.The proteins related to autoph-agy and AMPK/mammalian target of rapamycin(mTOR)signaling pathways were detected by w estern blot ting.Results The area of myocardial infarction in medium-dose and high-dose EE MO groups,and CD group was significantly smaller than that in model group(all P<0.05).The levels of serum creatine kinase(CK),creatine kinase MB(CK-MB)and myoglobin(Mb)in model group were significantly higher than those in sham operation group(all P<0.05),which were significantly lower in medium-dose and high-dose EE-MO groups,and CD group than in model group(all P<0.05).Compared with sham operation group,levels of left ventricular fractional shortening(LVFS)and left ventricular ejection fraction(LVEF)were decreased in model group,while left ventricular end diastolic diameter(LV EDd)and left ventricular end systolic diameter(LVESd)were inc reased(all P<0.05).Compared with model group,LVFS and LVEF were significantly increased in medium-dose and high-dose EE-MO groups and CD group,while LVEDd and LVESd were significantly decreased(all P<0.05).EE-MO could improve pa tho-logical damage of myocardial tissues and reduce score of myocardial injury(P<0.05).Compared with sham operation group,levels of Beclinl and LC3 I/LC3 I in myocardial tissues were significantly increased in model group,while levels of p62,p-AMPK/AMPK and p-mTOR/mTOR were significantly decreased(all P<0.05).Compared with model group,levels of Beclinl and LC3 II/LC3 I in myocardial tissues were significantly decreased in medium-dose and high-dose EE MO groups,and CD group,while levels of p62,p-AMPK/AMPK and p-mTOR/mTOR were significantly increased(all P<0.05).Conclusion EE MO could protect myocardial tissues through autophagy mediated by AMPK signaling pathways.