七氟醚后处理对大鼠心肌缺血再灌注损伤时线粒体融合蛋白-1表达的影响

Effects of sevoflurane postconditioning on expression of mitofusin 1 during myocardial ischemia-reperfusion injury in rats

目的 评价七氟醚后处理对大鼠心肌缺血再灌注损伤时线粒体融合蛋白-1（Mfn-1）表达的影响.方法 雄性SD大鼠40只,体重220 - 280 g,采用随机数字表法将其分为5组（n=8）：假手术组（S组）、缺血再灌注组（I/R组）、七氟醚后处理组（SP组）、七氟醚后处理＋线粒体ATP敏感性钾通道（mito-KATP）特异性阻断剂5-羟基癸酸盐（5-HD）组（SP＋ 5-HD组）、七氟醚后处理＋二甲基亚砜（DMSO）组（SP＋ DMSO组）.采用结扎左冠状动脉前降支30 min再灌注120 min的方法建立心肌缺血再灌注损伤模型.SP组、SP＋ 5-HD组和SP＋ DMSO组于再灌注前1 min时吸入七氟醚,呼气末浓度2.5％,持续吸入5 min;SP＋ 5-HD组于再灌注前15 min尾静脉注射5-HD 5 mg/kg,SP＋ DMSO组注射等容量DMSO.于再灌注120 min时处死大鼠,取左心室心肌组织,光镜下观察心肌组织病理学结果,透射电镜下观察心肌细胞超微结构,采用荧光定量PCR法测定心肌组织Mfn-1 mRNA表达,采用免疫组化法测定心肌组织Mfn-1蛋白表达.结果 与S组比较,其余4组心肌组织Mfn-1 mRNA及其蛋白表达下调（P＜0.05）,心肌病理学损伤明显;与I/R组比较,SP组和SP＋ DMSO组心肌组织Mfn-1 mRNA及其蛋白表达上调（P＜0.05）,SP＋ 5-HD组心肌组织Mfn-1 mRNA及其蛋白表达差异无统计学意义（P＞0.05）;与SP组比较,SP＋ DMSO组心肌组织Mfn-1 mRNA和蛋白表达差异无统计学意义（P＞0.05）.SP组心肌组织病理学损伤明显轻于I/R组和SP＋ 5-HD组.结论 七氟醚后处理可能通过开放mito-KATP上调Mfn-1的表达,减轻大鼠心肌缺血再灌注损伤.

Objective To evaluate the effects of sevoflurane postconditioning on the expression of mitofusin 1 （Mfn-1） during myocardial ischemia-reperfusion （I/R） injury in rats.Methods Forty healthy adult male Sprague-Dawley rats,weighing 220-280 g,were randomly divided into 5 groups （n =8 each） using a random number table：sham operation group （group S）,group I/R,sevoflurane postconditioning group （group SP）,sevoflurane postconditioning ＋ 5-HD （specific mitochondrial ATP-sensitive potassium channel blocker） group （group SP ＋ 5-HD）,and sevoflurane postconditioning ＋ dimethyl sulfoxide （DMSO） group （group SP ＋ DMSO）.Myocardial ischemia was induced by 30 min occlusion of left anterior descending branch of coronary artery followed by 120 min reperfusion.In SP,SP ＋ 5-HD and SP ＋ DMSO groups,sevoflurane was inhaled for 5 min after the end-tidal concentration reached 2.5% starting from 1 min before reperfusion.In group SP ＋ 5-HD,5-HD 5 mg/kg was injected via the caudal vein at 15 min before reperfusion,and the equal volume of DMSO was given in group SP ＋ DMSO.At 120 min of reperfusion,the rats were sacrificed and the hearts were removed.The myocardial specimens were taken from the left ventricle for examination of the pathological changes （by light microscopy） and ultrastructure of myocardial cells （by electron microscopy）,and for determination of the expression of Mfn-1 mRNA （by fluorescent quantitative PCR） and protein （by immunohistochemistry）.Results Compared with group S,the expression of myocardial Mfn-1 mRNA and protein was significantly down-regulated in the other four groups.Compared with group I/R,the expression of myocardial Mfn-1 mRNA and protein was significantly up-regulated in SP and SP ＋ DMSO groups,and no significant change was observed in the expression of myocardial Mfn-1 mRNA and protein in group SP ＋ 5-HD.There was no significant difference in the expression of myocardial Mfn-1 mRNA and protein between SP ＋ DMSO and SP groups.Compared with group I/R,the pathological changes of myocardial tissues were significantly attenuated in group SP.Conclusion Sevoflurane postconditioning reduces myocardial I/R injury possibly through opening mitochondrial ATP-sensitive potassium channel and up-regulating Mfn-1 expression in rats.