血管生成素样蛋白-4在通心络保护内皮屏障减轻心肌缺血再灌注损伤中的核心作用和机制

Myocardial ischemia-reperfusion injury has been the main obstacle to myocardial protection in the times of myocardial reperfusion therapy for acute myocardial infarction (AMI). Our previous studies have demonstrated that the effect of Tongxinluo against myocardial no-reflow and reperfusion injury is associated with the protection of vascular endothelial function and structure, and angiopoietin-like 4 might be the central protector in cardiac protection of Tongxinluo. In this study, we therefore further hypothesized that, the effect of Tongxinluo against myocardial ischemia-reperfusion injury should be realized through ANGPTL4 by protecting endothelial barrier function, and PPAR-α/ANGPTL4/Integrin pathway-mediated protection of endothelial cell-matrix adhesive junctions should be the underlying mechanism in protecting endothelial tight junctions and adherens junctions. To testify this scientific hypothesis, in vivo study will be performed in I/R model of SD rats, treated with Tongxinluo, rhANGPT4, PPAR-a inhibitor MK886, angptl4 siRNA, and integrin siRNA. Pathological, immunohistological, and molecular biological methods will be utilized to study the role and mechanism of PPAR-α/ANGPTL4/Integrin pathway in protecting endothelial barrier function, and thereby in reducing myocardial ischemia-reperfusion injury, including myocardial inflammation, oxidative stress, mitochondrial injury, apoptosis, autophagy, and necrosis. The results of present study will be helpful for us to clarify the central mechanism of myocardial ischemia-reperfusion injury, and be helpful either for our future development and application of cardioprotection drugs in the clinical setting after revascularization of AMI. Our original study is groundbreaking because of its important scientific and clinical value.

在我们系列研究的基础上，进一步假设：“通心络减轻心肌缺血-再灌注损伤（I/R）的作用，主要是通过血管生成素样蛋白4（ANGPTL4）对内皮屏障的核心保护作用而实现，而PPAR-α/ANGPTL4/Integrin通路保护内皮细胞-基质间粘附连接，是保护内皮屏障功能的基础和核心机制”。拟以SD大鼠建立心肌I/R模型，以通心络、rhANGPTL4、PPAR-α抑制剂MK886、ANGPTL4基因siRNA和Integrin基因siRNA作为干预措施，以病理学、免疫组学和分子生物学等方法，研究ANGPTL4在通心络保护内皮屏障功能，及减轻再灌注后心肌炎症反应、氧化应激、心肌凋亡和坏死中的核心作用和机制。为揭示内皮屏障功能在心肌I/R损伤产生、及通心络对其保护中的共同核心机制和核心保护因子提供科学依据，也为心肌I/R损伤防治和新药研发提供全新策略。具有重大的科学价值、临床意义和突出的原创性。

急性心肌梗死（AMI）是危害中国人民健康的第一杀手。作为治疗AMI的首选方法，早期冠脉再灌注疗法虽然可使堵塞冠状动脉迅速再通，恢复心肌供血供氧，改善患者预后，但是冠脉大血管再通后仍然可因微血管痉挛、微栓子栓塞和/或微血栓形成及结构损伤或破坏至其堵塞导致心肌再灌注损伤和无复流，最终使患者预后恶化；与此同时，中国幅员辽阔以及地区医疗水平参差不齐，由于错过早期冠脉开通最佳时间而导致心肌大面积不可逆性损伤也使得患者预后严重恶化。针对上述问题，本课题组主要研究中药通心络减轻急性心肌梗死缺血再灌注损伤核心作用机制和主要信号通路。基于本课题组前期研究发现的通心络通过激活PKA/eNOS以及MERK/ERK信号通路保护心肌微血管内皮屏障减轻心肌缺血再灌注损伤，本课题最新研究证明非糖尿病瘦鼠和糖尿病鼠AMI再灌注后均致心肌再灌注损伤、心脏微血管内皮细胞凋亡及内皮屏障功能损伤，且糖尿病鼠损伤更重。胰岛素、Angptl4和TXL均能保护糖尿病鼠AMI再灌注后的心肌再灌注损伤、心脏微血管内皮细胞凋亡及内皮屏障功能损伤，且TXL的保护效果不亚于胰岛素和Angptl4。TXL能够保护糖尿病鼠AMI再灌注后的心肌再灌注损伤、心脏微血管内皮细胞凋亡及内皮屏障功能损伤；Angptl4可能是其核心保护物质。TXL对糖尿病再灌注心肌的保护作用与其通过PPARα通路上调Angptl4有关。此外，本课题证实通心络可以通过激活miRNA128-3p/p70s6k1信号通路和AMPK/mTOR信号通路直接保护再灌注心肌。