Mechanism of myocardial ischemia/reperfusion-induced acute lung injury and protective effect of ischemic postconditioning / 中华创伤杂志

ABSTRACT

Objective To investigate the mechanism of myocardial ischemia and reperfusion-induced acute lung injury (ALl) and protective effect of ischemic postconditioning.Methods Forty SD rats were allocated to sham group,myocardial ischemia/reperfusion group (reperfusion group),ischemic postconditioning group (postconditioning group),and ischemic postconditioning + phosphatase and tensin homolog deleted on chromosome ten (PTEN) inhibiting group (inhibitor group) according to the random number table,with 10 rats per group.Myocardial ischemia/reperfusion was induced by left anterior descending coronary artery occlusion.Postconditioning was performed within 1 minute before reperfusion consisting of 3 10 s cycles of reperfusion followed by 10 s occlusion.Lung was immediately removed 120 minutes after reperfusion for HE stain,immunohistochemical detection of inflammatory factors and apoptosis factors,TUNEL assay of cell apoptosis,and Western blot of protein kinase B (Akt),phospho-Akt (p-Akt),glycogen synthase kinase-3β (GSK-3β),and phospho-GSK-3β (p-GSK-3β).Results Down-regulated B-cell lymphoma-2 (Bcl-2) and IL-10 and up-regulated Bcl-2 associated X protein (Bax),cysteinyl aspartate specific proteinase-3 (Caspase-3),IL-6 as well as IL-8 were observed in other 3 groups compared with sham group (P ＜0.01).Moreover,down-regulated Bax,Caspase-3,IL-6,IL-8 as well as TUNEL and up-regulated Bcl-2 as well as IL-10 were observed in reperfusion group compared to postconditioning group and tensor group (P ＜ 0.01).No statistical differences were found among the four groups in levels of Akt,p-Akt,and GSK-3β,but level of p-GSK-3β was significantly down-regulated in reperfusion group compared to other 3 groups(P ＜ 0.01).Conclusion Development of ALI may relate to down-regulation of p-GSK-3β evoked directly by the release of inflammation factors in early period of myocardial ischemia/reperfusion and ischemic postconditioning may attenuate the condition.