远程缺血预处理晚期相保护效应的可转移性及血浆exosome在此转移性保护中的作用和初步机制

Remote ischemic preconditioning (RIPC) could reduce ischemia reperfusion injury and had an early and a late phase of protection. Although late-phase protection lasted long and had multiple effects, the late occurrence limited its application and the underlying mechanism was unclear. The transferred preconditioning and the role of exosome in the signal transport of cardiac protection aroused great interest, but the transferability of late phase protection and the role of exosome in this transferred protection was unknown. Our previous studies showed that the preconditioned plasma obtained at the late phase of RIPC could reduce the infarct size, attenuate cardiac cell injury and activate the reperfusion injury salvage kinases (RISK) pathway, and the concentration of exosome increased in preconditioned plasma, suggesting the transferability of late phase protection and the importance of exosome. Therefore we proposed the hypothesis that late phase protection induced by remote ischemic preconditioning could be transferred between individuals and the plasma exosome mediated this transferred protection and activated the RISK pathway to confer protection. We planned to select indexes such as infarct size and cell apoptosis on in vivo and in vitro models to ①observe the transferability of late phase protection ②identify the role of plasma exosome in the transferred protection through adding, removing, and exchanging the exosome in preconditioned and non-preconditioned plasma③explore the signal pathway of conferring transferred protection in the cardiac cell . This study opened new possibilities of clinical application of late phase protection induced by RIPC and provided new clues of its underlying mechanism.

远程缺血预处理可减轻缺血再灌注损伤并有早期相和晚期相效应，虽然晚期相持久、效应多重，但因出现晚限制其应用，且其机制尚不清楚。预处理可转移性及exosome在心肌保护信号传递中的作用成为研究热点，但晚期相的可转移性及exosome在其中的作用尚无报道。我们预实验发现晚期相血浆减少心梗面积、减轻心肌细胞损伤及激活再灌注挽救激酶通路，且血浆exosome浓度升高，提示晚期相可转移性及exosome的潜在作用，故提出假说：远程缺血预处理晚期保护可在个体间转移，exosome介导此转移性保护且通过激活心肌细胞内RISK通路发挥作用。本项目拟利用动物及细胞再灌注损伤模型、采用心梗面积和细胞凋亡等指标①研究晚期保护的可转移性②通过加入/去除/互换exosome从多角度明确其在转移性保护中的作用③探讨转移性保护在心肌细胞内的信号通路。本项目为远程缺血预处理晚期保护的应用开辟新途径，为其机制提供新线索。

心肌缺血再灌注(Ischemia Reperfusion，IR)损伤在临床治疗中经常出现，有效地减轻再灌注损伤是改善心肌梗死临床预后的关键。远程缺血预处理（RIPC）可减轻缺血再灌注损伤并有早期相和晚期相效应，虽然晚期相持久、效应多重，但因出现晚限制其应用，且其机制尚不清楚。预处理可转移性及外泌体在心肌保护信号传递中的作用成为研究热点，但晚期相的可转移性及外泌体在其中的作用尚无报道。本研究利用在体心肌缺血再灌注模型和离体心肌细胞缺氧复氧模型，从心梗面积、心功能和心肌细胞凋亡等方面研究RIPC 晚期相保护效应是否可以通过血浆或外泌体转移，并研究RISK通路的激活情况以初步探讨外泌体心肌保护作用的机制，结果缺血前24h和再灌注时输注RIPC晚期相血浆或外泌体可减轻经历缺血再灌注损伤大鼠心肌心肌梗死面积、改善心脏的射血分数，并增加RISK通路相关蛋白如Akt和GSK3β的磷酸化水平，而去外泌体血浆上述效果不明显；RIPC晚期相血浆/外泌体可改善缺氧复氧后心肌细胞活力，减少心肌细胞凋亡，减少促凋亡蛋白的表达，并激活RISK通路，抑制RISK通路后，其保护作用消失。本研究结果证实了RIPC晚期相血浆外泌体的心肌保护作用，揭示了RIPC晚期相的心肌保护机制，为RIPC晚期相血浆外泌体应用到临床提供了理论依据。

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