NMDA-R/mtDNA介导的线粒体损伤和炎性凋亡在急性心肌缺氧损伤中的作用研究及薯蓣皂苷的干预机制

The increasing burden of acute myocardial infarction (AMI) makes it become one of the major public health problems that need to be solved urgently. Although it is well-known that mitochondrial damage is involved in the AMI, the detailed mechanism is still unclear. Our previous study found the glutamates metabolism was disrupted in AMI murine model by metabonomic analysis. The present study aims to explore the roles of NMDA-R-mediated mitochondrial damage and mitochondrial DNA-induced pyroptosis in the AMI-induced myocardial injury. In addition, with the treatment of Diosgenin-A (DN-A), previous study showed its protective effects on the myocardial injury by disruption of glutamates metabolism and calcium influx-related metabolism. The present study aims to prove that DN-A had protective effects on the AMI-induced myocardial injury through inhibiting NMDA-R/Ca2+/mROS/mtDNA/NLRP3/Caspase-1 signaling pathway. Our study can provide novel insights and targets for the treatment of AMI through exploring the detailed pathological mechanism on molecular and subcellular organelles levels, which is important for the theoretic and therapeutic values.

急性心肌梗死（AMI）的疾病负担正在日益加重，已成为亟待解决的重大公共卫生问题。尽管已有研究证实AMI后存在线粒体损伤，但其中的具体机制仍有待探究。前期通过建立AMI小鼠模型，采用代谢组学方法分析发现发现谷氨酸盐代谢出现了明显异常。本研究拟通过急性缺氧细胞及小鼠模型，探究NMDA-R作为一种谷氨酸盐钙通道受体介导的线粒体损伤以及线粒体DNA介导的炎性凋亡在AMI心肌损伤中的作用。另外，给予薯蓣呋甾烷型皂苷A（DN-A）干预，前期代谢组学分析提示其主要通过影响谷氨酸代谢以及钙离子过载相关代谢而发挥心肌保护作用。通过本课题研究，验证DN-A通过NMDA-R/Ca2+/mROS/mtDNA/NLRP3/Caspase-1发挥心肌保护作用。本课题的完成，将为AMI的治疗提供一种新的思路与靶点，从蛋白分子及亚细胞器水平丰富AMI的病理机制及中药治疗的疗效机理，具有十分重要的理论意义和应用价值。

急性心肌梗死(AMI)的疾病负担正在日益加重，已成为亟待解决的重大公共卫生问题。尽管已有研究证实AMI后存在线粒体损伤，但其中的具体机制仍有待探究。本研究前期通过建立AMI小鼠模型，采用代谢组学方法分析发现发现谷氨酸盐代谢出现了明显异常。本研究进一步发现NMDAR的特异性激动剂NMDA在缺氧条件下可以明显加重细胞的死亡，我们发现缺氧情况NMDA可以诱导Caspase-3途径的细胞凋亡。而给予NMDA-R的特异性抑制剂MK-801，缺氧损伤导致的细胞凋亡水平明显降低，电镜照片发现线粒体损伤明显，线粒体损伤介导的细胞凋亡关键分子蛋白Bax、Bcl-2均明显升高，且可以被MK-801抑制。进一步探究线粒体损伤我们发现线粒体膜电势在缺氧刺激下明显升高，mitoSOX和钙离子水平也明显升高，说明线粒体的氧化应激损伤明显，而通过抑制NMDA-R可以显著降低钙超载介导的线粒体氧化应激损伤么，最终对心肌细胞起到保护作用。本课题的完成，将为AMI的治疗提供一种新的思路与靶点，为进一步设计防止AMI的药物提供了理论基础。