分子氢减轻心肌缺血再灌注损伤的膜分子机制研究

Overproduction of oxygen free radicals (ORSs) plays a pivotal role in myocardial ischemia reperfusion (I/R) injury. Our previous research demonstrated that hydrogen could protect against myocardial I/R injury by cleaning up ORSs selectively, however, the exact mechanism is not clear. Our preliminary results showed that hydrogen exerted an influence on membrane fluidity and permeability and reduced calcium influx. Hydrogen might mitigate calcium overload by cleaning up ORSs and improving biophysical characteristics of lipid bilayer membranes. This study is designed to investigate the effect of hydrogen on membrane fluidity and permeability as well as membrane L-calcium channel proteins against I/R injury by using laser scanning confocal microscope, electron spin resonance imaging and Raman spectroscopy. Our research will focus on hydrogen's effect on cardiac myocyte membrane permeability and membrane calcium distribution. The understanding of the role hydrogen plays in influencing cardiac myocyte membrane structure and function and reducing intracellular calcium overload will help clarify the molecular mechanism of hydrogen in protecting myocardial cells, which might provide a new vision and novel therapies for clinical cardioprotection.

氧自由基（OFR）的过量产生和聚集是心肌缺血再灌注（IR）损伤发生和发展的枢纽性环节。研究表明氢可选择性清除OFR，发挥对IR损伤的保护作用，但确切的机制不清。我们前期实验证实，分子氢可改善IR心肌细胞的膜脂组份和流动性，减少钙内流。提示氢可能通过选择性清除OFR，改善细胞膜脂质双分子层的生物物理特性，减轻细胞内钙超载。本项目应用自旋标记-电子自旋共振、激光扫描共聚焦和膜片钳等技术手段，从细胞和整体心脏水平进一步观察分子氢对心肌细胞的膜脂组份、流动性以及细胞膜L-型钙通道蛋白构象等的影响，重点探讨其对心肌细胞膜通透性以及细胞内钙含量和膜内外钙流量的作用，明确氢是否可通过影响心肌细胞膜脂及膜蛋白结构和功能，改善细胞膜通透性，减轻细胞内钙超载，抑制心肌细胞凋亡发生，发挥其对心肌IR损伤的保护作用。本研究有望阐明分子氢发挥心肌保护作用的膜分子机制，为临床心肌保护提供新的思路和治疗靶点。

体外循环引起的缺血再灌注（IR）损伤，仍然是影响心脏手术临床疗效的重要制约因素。氧自由基的大量产生、心肌细胞钙超载在IR损伤中扮演着重要的角色。我们初步研究结果显示：分子氢能够选择性清除体内过量产生的氧自由基，缓解心肌缺血再灌注损伤，但具体机制不明。.本项目利用了自旋标记-电子自旋共振、激光扫描共聚焦和膜片钳等技术手段，从细胞和整体心脏水平观察分子氢对心肌细胞的膜脂组份、流动性以及L-型钙通道蛋白流量等的影响，特别是对心肌细胞膜通透性以及对细胞膜钙超载、心肌细胞凋亡的影响，明确分子氢是否可通过选择性抗氧化，稳定细胞膜组分及其流动性，从而减少细胞膜通透性、减轻钙超载，发挥心肌缺血再灌注损伤的保护作用。.结果发现：1、分子氢在IR过程中可以选择性清除过量产生的毒性自由基；2、分子氢可以改善IR诱导的细胞膜脂组分改变及流动性改变，从而减少心肌细胞膜通透性；3、分子氢可以减轻再灌注过程中的心肌细胞钙超载，抑制凋亡，从而发挥对再灌注损伤的保护作用。