基于p53-SIRT1-miR-34a反馈环路研究血府逐瘀汤抗心肌缺血大鼠内皮祖细胞衰老的作用与机理

Coronary artery disease is a common reason for myocardial ischemia,dedicated to one of the leading causes of death.It has been proven that neovascularization is an important therapy for recovery of the ischemic heart's structure and function.Endothelial progenitor cells(EPCs) are the key factor for ischemic heart neovascularization.However, EPCs fall into senescence state in cardiovascular disease,affecting its number and functions and severely impeding neovascularization after myocardial ischemia. Explicit evidence showed that there was a strong correlation between p53—SIRT1—miR-34a feedback loop and EPCs senescence.Previous experiments indicated that Xuefu Zhuyu Decoction, a formula representing effect of promoting blood to remove blood stasis,could facilitate neovacularization by improve EPCs number and function,but the mechanism is still ambiguous.Hence, this study was aimed to explore effect of Xuefu Zhuyu Decoction preventing EPCs from senescence to accelerate neovacularization in vitro and vivo through rat myocardial ischemia model and techniques of cytobiological and molecular technologies. Moreover, to detect the expressions of p53,SIRT1 and miR-34a confirm whether Xuefu Zhuyu Decoction can prevent EPCs from senescence via miR-34a—SIRT1 feedback loop.It is significant for deep understanding of activating blood to remove stasis theory and promotion of traditional Chinese medicine for prevention and treatment in cardiovascular and cerebrovascular diseases.

冠心病常导致心肌缺血，严重危害人类健康。血管新生可促进心肌缺血后心脏形态和功能恢复，而内皮祖细胞（EPCs）是参与血管新生的关键细胞。EPCs衰老导致其数量和功能异常，使心血管病患者血管新生受阻，而miR-34a—SIRT1—p53反馈环路与EPCs的衰老密切相关。前期研究发现，血府逐瘀汤可提高EPCs的水平和功能，促进血管新生，但机制尚不明确。据此，本课题拟制备心肌缺血大鼠模型，综合运用细胞生物学和分子生物学等技术，从体内和体外两个层面研究血府逐瘀汤抗EPCs衰老的效应，并通过对p53、SIRT1、miR-34a的检测探究血府逐瘀汤影响p53—SIRT1—miR-34a环路与延缓EPCs衰老的关系，挖掘血府逐瘀汤促血管新生的新机制。预期本研究对揭示中医药活血化瘀法的作用机制，促进中医药在心脑血管疾病防治中的应用具有重要的科学意义。

本课题组采用大鼠骨髓源EPCs衰老模型、心肌缺血大鼠模型，以血府逐瘀汤为代表方，以EPCs衰老为切入点，探讨血管新生的可能机制。主要进行了血府逐瘀汤抗大鼠骨髓源EPCs衰老作用及机制研究、血府逐瘀汤促进大鼠骨髓源EPCs转化为新生血管内皮细胞的观测、血府逐瘀汤诱导EPCs参与心肌缺血大鼠缺血区血管新生的实验研究以及血府逐瘀汤抗心肌缺血大鼠外周血EPCs衰老作用及机制研究。实验结果表明，血府逐瘀汤可以抑制miR-34a的表达、下调p53的表达，上调SIRT1的表达，延缓EPCs衰老，增强EPCs的迁移能力，促进EPCs转化为新生血管内皮细胞，增强心肌缺血区血管新生能力。因此，我们认为血府逐瘀汤延缓EPCs的衰老，增强其血管新生能力，促进心肌缺血区血管新生，与p53-SIRT1-miR-34a正反馈调节环路有关。