二氢丹参酮抑制NLRP3炎症体对血透诱导心肌缺血再灌注损伤的保护作用机制研究

The morbidity and mortality of cardiovascular events in maintaining hemodialysis patients remains high in recent years, endangering the quality of patients’ life. Volume fluctuations during hemodialysis lead to myocardial ischemia-reperfusion injury. Concurrent studies show immune and inflammation plays an important role in the pathophysiology of myocardial ischemia-reperfusion injury. Our previous studies discovered: ① Increased expression of NLRP3 inflammasome and its downstream inflammatory medium after ischemia-reperfusion injury in mice. ②The expression of NLRP3 inflammasome was inhibited by Salvia miltiorrhiza, improving myocardial ischemia-reperfusion injury. In this context, this project will be further discussed in simulated MHD rat model in the following aspects: ① The effect of the extent and speed of volume drop during hemodialysis on cardiac structure and function. ② The mechanism of hemodialysis-induced TLR4-NFκB-NLRP3 inflammasome signaling pathways involved in myocardial ischemia-reperfusion injury. ③ Dihydrotanshinone, one of the major components of Danshen, is used to investigate the protective effect of blocking the signal pathway of TLR4-NFκB-NLRP3 inflammasome on hemodialysis-induced myocardial ischemia-reperfusion injury. This will provide new intervention strategies and targets for hemodialysis-induced myocardial ischemia-reperfusion injury and cardiovascular events.

维持性血液透析（maintaining hemodialysis, MHD）患者心血管事件发生率和死亡率居高不下，严重影响患者的生存质量。透析过程中容量波动易导致心肌缺血再灌注损伤（I/R）。免疫炎症在心肌I/R损伤病理生理过程中起到重要作用。我们前期研究发现：①小鼠I/R损伤后NLRP3炎症体及其下游炎症介质表达升高；②丹参抑制NLRP3炎症体表达，改善心肌I/R损伤。在此基础上，本项目将在模拟MHD大鼠模型中进一步探讨：①MHD容量下降程度和速度对心脏结构和功能的影响；②MHD过程诱导TLR4-NFκB-NLRP3炎症体信号通路参与I/R损伤的具体机制；③利用二氢丹参酮（中药丹参的重要组成成分之一），探讨阻抑TLR4-NFκB-NLRP3炎症体信号通路对血透诱导的I/R的保护性作用。从而为MHD缺血再灌注损伤及心血管事件发生提供新的干预策略和靶点。

【背景】血透透析容量波动导致的低血压是血透过程中最常见并发症，低血压诱发缺血再灌注损伤（ischemia reperfusion, I/R）是心肌损伤的重要环节，免疫炎症参与心肌I/R损伤。然而，针对血液透析容量快速下降引起心脏I/R损伤的病理生理机制研究甚少。【方法】构建5/6肾切除大鼠模型。心超评估心脏功能；Western blot检测NLRP3炎症体及其下游的表达水平；免疫组化法检测IL-1β、NF-κB在心脏表达。丹参乙酸镁干预急性肾损伤。【结果】（1）血液透析后，高超滤率（high ultrafiltration rate, HUFR）组较低超滤率（low ultrafiltration rate, LUFR）组心功能明显更差（P<0.01）、心肌缺血梗死面积更大（P<0.05）；HUFR组引起的心脏I/R损伤显著上调caspase-1和成熟IL-1β的表达（P<0.05）。而对NLRP3 KO大鼠，上述两组无差异。（2）血液透析后，HUFR组较Sham组TLR4、NF-κB、IL-6及IL-1β表达升高（P<0.05），NLRP3 KO组及TAK-242组较HUFR组NF-κB、IL-6及IL-1β的表达下降（P<0.05）；HUFR组较Sham组NLRP3、ASC、Casp-1升高（P<0.05），NLRP3 KO组的Casp-1无表达、较HURF组ASC及IL-18表达明显下降（P<0.05），TAK-242组较HUFR组的ASC表达下降（P<0.05）。（3）丹参乙酸镁预处理显著减轻急性肾损伤的肾脏肿胀，并缓解肾脏指数的增加；血肌酐在丹参乙酸镁干预后显著下降；组织病理学结果显示肾小管的损伤显著减轻；KIM-1和NGAL在丹参乙酸镁干预后显著降低。【结论】血液透析过程中的容量波动通过TLR4-NFκB-NLRP3炎症体信号通路参与心脏I/R损伤。丹参乙酸镁对急性肾损伤有保护作用。