Role Of Autophagy In Sevoflurane Preconditioning Mediated Delayed Myocardial Protection On Rat Cardiomyocytes Against Hypoxia/Reoxgenation Injury

ObjectiveTo investigate the delagyed protection of Sevoflurane preconditioning (SWOP) against myocardial hypoxia/reoxgenation (H/R) injury and the mechanism of autophagy during the cardioprotection on rat cardiomyocytes.MethodsIn this study, H9c2 rat cardiomyocytes were randomly divided into five groups: Control (CON) group; H/R group, rat cardiomyocytes was exposed in the airtight container for 2 h followed by 1 h of reoxgenation; SWOP group, rat cardiomyocytes was exposed to 1 h of 2.5% sevoflurane 24 h before H/R; The inhibitor of autophagy 3-methyladenine (3-MA) was added to culture medium 15 min before sevoflurane exposure (3-MA+SWOP group) or cells were treated by 3-MA alone (3-MA group). Rat myocardiocytes were collected after different treatments. Cell proliferation was detected by MTT assay. Apoptosis rate was analyzed by flow cytometry. Autophagosomes and apoptosis were observed with transmission electron microscopy (TEM). The expression of autophagy protein microtubule associated protein light chain3-Ⅱ(LC3-Ⅱ), Beclin 1 and anti-apoptosis factor B-cell lymphoma-2 (Bcl-2) was determined by western blot.ResultsThe cell proliferation of SWOP group, 3-MA group and 3-MA+SWOP group were significantly increased compared with the H/R group (P<0.05), and the apoptosis rate was decreased (P<0.05). TEM releaved that the formation of autophagosome and apoptosis was decreased in the sevoflurance preconditioning groups compared with the H/R groups. The expression of LC3-Ⅱand Beclin 1 were upregulated in H/R and SWOP groups compared with CON group (P<0.05), which were lower in SWOP group, 3-MA group and 3-MA+SWOP group than in H/R group, but Bcl-2 expression was upregulated.ConclusionThe results of our study indicated that Sevoflurane preconditioning (SWOP) 24 h before H/R produced delayed myocardial protection against H/R injury by increasing cell proliferation and decreasing apoptosis rate in cardiomyocytes. SWOP may inhibit autophagic cell death and apoptosis by down-regulation of autophagy protein LC3-Ⅱand Beclin 1 expression and up-regulation of Bcl-2 expression during reoxgenation.