Role of autophagosomes clearance in delayed cardioprotection in rats with ischemia-reperfusion injury by sevoflurane preconditioning in vivo

Abstract

Objective To evaluate role of autophagosomes clearance in delayed cardioprotection by sevoflurane preconditioning in rats with ischemia-reperfusion injury in vivo. Methods Forty-five adult male Sprague-Dawley rats, weighing 270-350 g, were randomly(random number) divided into 3 groups: sham operation group (sham group), ischemia-reperfusion group (CON group), sevoflurane preconditioning group (SWOP group). Myocardial ischemia was induced by 30 min occlusion of left anterior descending branch (LAD) of coronary artery followed by reperfusion for 2 h, and myocardial infarct size was stained by triphenyltetrazolium chloride. Cardiomyocyte apoptosis was evaluated by terminal deoxyribonucleotidyl transferase-mediated biotin-16dUTP nick-end labeling. Autophagosomes were detected under transmission electron microscope.Expression of LC3-Ⅱ, cathepsin B, p62 and cleaved caspase-3 were assessed by western blotting. Statistical analysis were performed using one or two way analysis of variance (SPSS 15.0, Chicago, USA) test followed by Dunnet-t or LSD-t test. Results Sevoflurane preconditioning reduced myocardial infarct size and the number of autophagosomes (P=0.027), attenuated cardiomyocyte apoptosis (P=0.042). Sevoflurane preconditioning decreased the level of LC3-Ⅱ (P=0.033), p62 (P=0.041) and cleaved caspase-3 (P=0.037), but increased the level of cathepsin B (P=0.046). Conclusions Delayed cardioprotection by sevoflurane preconditioning increased myocardial clearance of autophagosomes against the delayed ischemia reperfusion injury. Key words: Anesthetic, inhalation; Myocardial reperfusion injury; Autophagy; Apoptosis; Lysosome