摘要
目的 探讨脑缺血/再灌注(CI/R)不同时间心肌损伤及机体自我保护机制自噬的的动态变化及分子机制。方法 采用雄性Sprague-Dawley大鼠建立CI/R模型。按照再灌注时间将大脑中动脉闭塞后CI/R大鼠分为6、12、24和48 h组。采用活性氧(ROS)、活性氮(RNS)检测指标评估心肌氧化应激损伤。观察各组大鼠心肌细胞凋亡和自噬体结构,检测心肌自噬、自噬流以及自噬调控蛋白和基因表达的动态变化。结果 大鼠CI/R后心肌发生氧化应激损伤及凋亡,心肌细胞内自噬体增加,在12 h达高峰,自噬流在CI/R前12 h内被破坏,心肌内自噬调节蛋白Beclin 1、mTOR、AMPK在CI/R后48 h表达增加,其表达趋势与自噬变化基本一致,与对照组比较差异均有统计学意义。结论 自噬在大鼠CI/R所致心肌损伤中起保护作用,Beclin 1介导的自噬/凋亡互反馈通路及mTOR介导的mTOR/自噬互反馈通路在调节自噬中起重要作用。
Objective To investigate the dynamic changes and molecular mechanisms of myocardial injury and autophagy as the body’s self-protective mechanism at different time points after cerebral ischemia/reperfusion(CI/R).Methods A CI/R model was established in male Sprague-Dawley rats using the Longa thread method.Rats that underwent CI/R following middle cerebral artery occlusion were classified into 6-,12-,24,and 48-hour groups according to the reperfusion time.The concentrations of reactive oxygen species and reactive nitrogen species were measured to evaluate myocardial oxidative stress.Cardiomyocyte apoptosis and autophagosomes were observed in the myocardium.Additionally,dynamic changes in myocardial autophagy,autophagic flux,and protein and gene expression of autophagy regulators were detected.Results Oxidative-stress-induced injury and apoptosis were observed in the myocardium after CI/R.The number of autophagosomes in cardiomyocytes increased,peaking in the 12 h group,and autophagic flux was impaired during the first 12 h after CI/R.Beclin 1,mammalian target of rapamycin(mTOR),and adenosine monophosphate-activated protein kinase(AMPK)expression levels in the myocardium increased during the first 48 h after CI/R,peaking in the 12 h group.This was consistent with changes in autophagy,which showed significant differences compared with the control group.Conclusion These results indicated that autophagy plays a protective role against CI/R-induced myocardial injury.Furthermore,Beclin 1-mediated autophagy/apoptosis and mTOR-mediated autophagy mutual feedback pathways play important roles in the regulation of autophagy.
作者
李晓婷
聂宏光
樊建华
LI Xiaoting;NIE Hongguang;FAN Jianhua(Hospital-Acquired Infection Control Department,The Fourth Affiliated Hospital of China Medical University,Shenyang 110032,China;Laboratory of Stem Cell and Regenerative Medicine Research,School of Basic Medicine,China Medical University,Shenyang 110122,China;Department of Neurology,The Fourth Affiliated Hospital of China Medical University,Shenyang 110032,China)
出处
《中国医科大学学报》
CAS
北大核心
2024年第7期603-609,共7页
Journal of China Medical University
基金
辽宁省重点研发计划指导计划(2018225077)。
