UCP2过表达调控线粒体动力学及超氧炫保护脓毒症心肌损伤研究

Protection of myocardial mitochondrial function plays an important role to treat septic myocardial injury and improve sepsis outcome. Uncoupling protein-2 (UCP2) is one of the transmembrane proteins mainly located in the inner mitochondrial membrane which downregulates the production of reactive oxygen species (ROS), inhibits inflammatory response and modulates mitochondrial respiratory chain function. Therefore, the present study is designed to transgenically overexpress UCP2 in the isolated heart and cultured cardiomyocytes to observe the protective effect on septic myocardial injury and the change of morphology and function of two type of mitochondria (interfibrillar mitochondria and subsarcolemmal mitochondria) using Langendorff apparatus. Then, the contractile function of endotoxin-induced cardiomyocyte injury is measured after transgenical UCP2 overexpression by Ionoptix myocam system. The change of the characteristics of mitochondrial dynamics and superoxide flashes are further detected in primary cultured cardiomyocytes with overexpression of UCP2 isolated from pan-tissue mt-cpYFP transgenic mice. The present study is aimed to verify the hypothesis that interaction between mitochondrial dynamics and superoxide flashes plays a vital role against septic myocardial injury through overexpressing UCP2 in myocardial mitochondria in order to quest for a new therapeutic target for myocardial protection during sepsis.

保护心肌线粒体功能对脓毒症心肌损害的治疗、改善脓毒症预后有重要价值。解偶联蛋白-2（UCP2）是主要存在于线粒体内膜的跨膜蛋白，其轻度解偶联作用具有抑制活性氧、炎性反应及调控线粒呼吸链功能的生理效应。本项目采用腺病毒UCP2载体基因转染技术，在活体心肌和心肌细胞过表达UCP2。离体心脏灌注模型观察UCP2过表达后对脓毒症心肌损伤的保护及两类线粒体（IFM 和SSM）形态结构及功能改变；原代培养大鼠心肌细胞，Ionoptix可视化动缘探测系统进一步验证UCP2过表达后对内毒素损伤心肌细胞收缩功能损伤的保护；泛表达cpYFP转基因小鼠心肌细胞原代培养，观察UCP2过表达后内毒素损伤心肌细胞线粒体动力学及超氧炫改变机制。本项目通过过表达心肌线粒体UCP2以观察线粒体动力学及超氧炫改变规律，探讨线粒体动力学及超氧炫是否存在互动机制并参与脓毒症心肌保护效应，为脓毒症心肌损伤保护提供新的治疗靶点。

保护心肌线粒体功能对脓毒症心肌损害的治疗、改善脓毒症预后有重要价值。解偶联蛋白-2（UCP2）是主要存在于线粒体内膜的跨膜蛋白，其轻度解偶联作用具有抑制活性氧、炎性反 应及调控线粒呼吸链功能的生理效应。本项目采用腺病毒UCP2载体基因转染技术，在活体心肌 和心肌细胞过表达UCP2。本研究发现：① 脓毒症心肌损伤时，EF及FS改变在正常范围，舒张期心室壁厚度增加；② 脓毒症可引起离体后的大鼠心脏收缩及舒张功能障碍以及超微结构损伤。③LPS刺激导致心肌细胞损伤，UCP2过表达能够减少脓毒症心肌细胞过量ROS的产生，逆转LPS刺激导致的心肌损伤，起到心肌保护作用。④UCP2过表达能在一定程度上改善脓毒症心肌收缩功能异常和能改善脓毒症心肌损伤线粒体功能障碍。⑤ UCP2过表达使ROS生成减少，降低Drp1蛋白的表达，通过抑制线粒体分裂，进而调控线粒体动力学，改善线粒体功能，发挥心肌保护的作用。本项目资助发表SCI论文1篇，北图核心论文1篇，核心综述2篇，2篇文章代发。培养硕士研究生3名，2名均获得硕士学位，1名在读。项目投入经费38.0万，支出34.9246万元，各项支出基本与预算相符。剩余经费计划用于本项目研究后续支出。