氢对老龄大鼠心肌缺血再灌注时线粒体融合的影响

Effect of hydrogen on mitochondrial fusion during myocardial ischemia-reperfusion in aged rats

目的 评价氢对老龄大鼠心肌缺血再灌注时线粒体融合的影响.方法 清洁级健康雄性SD大鼠150只,18月龄,体重400～500 g,采用随机数字表法分为5组（n=30）：对照组（C组）、假手术组（S组）、缺血再灌注组（I/R组）、生理盐水组（NS组）和富氢液组（H组）.C组不做任何处理;S组仅穿线不结扎;I/R组、NS组和H组采用结扎冠状动脉左前降支30 min恢复灌注的方法制备大鼠心肌缺血再灌注损伤模型;再灌注前5 min,NS组腹腔注射1ml/100 g生理盐水,H组腹腔注射1ml/100 g富氢液.于再灌注12和24h时每组随机取15只大鼠处死取心脏,光镜下观察病理学结果,采用TUNEL法观察心肌细胞凋亡情况,计算细胞凋亡指数,采用Western blot法检测心肌细胞线粒体融合蛋白1（Mfn1）和Mfn2的表达,RT-PCR法检测Mfn1和Mfn2的mRNA表达.结果 与C组和S组比较,I/R组、NS组和H组再灌注12和24h时心肌细胞凋亡指数增加,Mfn1和Mfn2及其mRNA的表达水平降低（P＜0.05）;与NS组和I/R组比较,H组再灌注12和24 h时心肌细胞凋亡指数降低,Mfn1和Mfn2及其mRNA的表达水平升高（P＜0.05）.H组心肌细胞病理学损伤程度较I/R组减轻.结论 氢减轻老龄大鼠心肌缺血再灌注损伤的机制与其促进线粒体融合,抑制心肌细胞凋亡有关.

Objective To evaluate the effect of hydrogen on mitochondrial fusion during myocardial ischemia-reperfusion （I/R） in aged rats.Methods One hundred and fifty pathogen-free healthy male Sprague-Dawley rats,aged 18 months old,weighing 400-500 g,were divided into 5 groups （n=30 each） using a random number table：control group （group C）,sham operation group （group S）,group I/R,normal saline group （group NS） and hydrogen-rich saline group （group H）.Group C received no treatment.The anterior descending branch was only exposed but not ligated in group S.Myocardial I/R was induced by occlusion of the anterior descending branch of the left coronary artery for 30 rmin followed by reperfusion in I/R,NS and H groups.Hydrogen-rich saline 1 ml/100 g was injected intraperitoneally at 5 min before reperfusion in group H,while normal saline 1 ml/100 g was injected intraperitoneally at 5 min before reperfusion in group NS.The rats were sacrificed at 12 and 24 h of reperfusion,and hearts were removed for examination of the pathological changes and for determination of apoptosis in cardiomyocytes （by TUNEL） and expression of Mfn1 and Mfn2 protein and mRNA in myocardial tissues （by Western blot or real-time polymerase chain reaction）.The apoptosis index was calculated.Results Compared with C and S groups,the apoptosis index of cardiomyocytes was significantly increased and the expression of Mfn1 and Mfn2 protein and mRNA in myocardial tissues was down-regulated at 12 and 24 h of reperfusion in I/R,NS and H groups （P〈0.05）.Compared with NS and I/R groups,the apoptosis index of cardiomyocytes was significantly decreased and the expression of Mfn1 and Mfn2 protein and mRNA in myocardial tissues was up-regulated at 12 and 24 h of reperfusion in group H （P〈0.05）.The pathological changes of myocardial tissues were significantly attenuated in group H when compared with group I/R.Conclusion The mechanism by which hydrogen attenuates myocardial I/R injury is related to promoting mitochondrial fusion and inhibiting apoptosis in cardiomyocytes of aged rats.