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

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. Key words: Anesthetics, inhalation ;  Myocardial reperfusion injury ;  Fusion proteins, bcr-abl