有氧康复运动通过EETs通路调节内皮祖细胞功能的机制研究

It has been stated clearly that cardiac rehabilitation is essential after myocardial infarction in the latest clinic guide. Aerobic exercise, key of the cardiac rehabilitation, has been proven to be effective in improving myocardial ischemia after myocardial infarction, but the mechanism is not clear. We found that epoxyeicosatrienoic acid (EETs) pathway was activated in mice after aerobic exercise. We also demonstrated that aerobic exercise promoted the function of mouse bone marrow derived endothelial progenitor cells (EPCs) after myocardial infarction, accompanied by significantly change of miR-126-3p, miR-92a expression which were closely associated with angiogenesis. Therefore we speculate that aerobic exercise affect the function of EPCs by regulating related miRNAs through EETs pathway, hereby promoting angiogenesis so as to increase myocardial blood supply after myocardial infarction. In order to prove this point, firstly, it will be demonstrated the effect of aerobic exercise on promoting angiogenesis after myocardial infarction in the present study. Then more importantly, it will be necessary to confirm that EETs mediate the change of related miRNAs induced by aerobic exercise. Thirdly, the specific signal transduction pathways modulated by EETs will be find out. Lastly it will be focused on verification of the role of the related miRNAs and their target genes on promoting angiogenesis by aerobic exercise. This study will improve the understanding the role of cardiac rehabilitation exercise on improving myocardial ischemia after myocardial infarction, and provide new theoretical basis and new ideas for cardiac rehabilitation.

最新指南已经明确心脏康复是心肌梗死后必不可少的治疗措施。以有氧运动为核心的心脏康复已被证明能有效改善心肌缺血,但其机制尚不明确。我们发现有氧运动可以激活小鼠体内环氧二十碳三烯酸(EETs)通路、调节心肌梗死后小鼠骨髓来源内皮祖细胞(EPCs)的功能,伴随细胞内与血管生成密切相关的微小RNA(miR)miR-126-3p和miR-92a的表达显著改变。因此推测有氧运动通过EETs通路调控相关miRNAs而影响EPCs的功能,进而促进心肌梗死后新生血管生成,增加心肌供血,改善心功能。为此本研究将首先明确有氧运动具有促进心肌梗死后血管生成的作用,接着重点证实EETs介导了有氧运动对相关miRNAs的调控，继而探明其具体的信号调节通路,然后通过验证相关miRNAs及其目的基因的作用以阐明有氧运动促进血管生成的机制。本研究将丰富心脏康复运动改善心肌缺血机制的认识,为心脏康复提供新的理论基础和新思路。

以有氧运动为核心内容的心脏康复是目前心血管疾病包括心肌梗死后治疗的必需措施之一。已有研究报道有氧运动可调节多重因素，如调控内皮祖细胞（EPCs）功能从而起到心血管保护作用。基于我们的前期研究发现心肌梗死后患者血浆中二十碳环氧三烯酸（EETs）浓度降低且体外加入环氧化酶抑制剂（sEHi）升高EETs浓度后可增强EPCs功能。我们推测有氧运动可能通过增加EETs浓度，调节EPCs功能，从而起到促进心肌梗死后缺血区毛细血管新生、缩小心肌梗死面积并改善心功能作用。. 本研究首先明确了有氧运动可促进心肌梗死后小鼠骨髓源性EPCs功能，且在运动4W时间点EPCs的功能达峰值。继续延长运动时间，EPCs功能可持续维持在相对活跃状态。接着，本项目验证了有氧运动可增加血浆中EETs浓度，并发现EETs浓度升高可促进小鼠骨髓源性EPCs功能从而增加心肌梗死缺血区毛细血管密度、缩小心肌梗死面积并改善心功能。在机制研究中，我们分别通过体内、外实验验证了在心肌梗死后小鼠中，运动诱导的血浆EETs浓度升高可进一步激活EPCs中AKT/GSK3β信号通路，从而调控EPCs中miR-126和miR-92a及其靶基因Spred1和Itga5的表达，增强心肌梗死后小鼠骨髓源性EPCs的功能及促进缺血区毛细血管新生，发挥缩小心肌梗死面积作用并改善心肌梗死后心功能。. 本研究验证了有氧运动对心肌梗死小鼠心脏缺血的保护作用，并阐述了其具体机制。本项目的实施有利于丰富对心脏康复运动有益作用的认识，为心脏康复寻找到新的基础研究依据，具有重要的研究价值和临床应用前景。