Role of the JAK2-STAT3 Pathway Mediates the Cardioprotection of Ischemic Postconditioning

Objective:To investigate the effect of ischemic postconditioning on myocardial infarction and myocardial apoptosis in ischemia-reperfusion injury of rats,and the protective mechanisms thereof. Methods:Thirty-six healthy male Wistar rats (230-280 g) were randomly divided into three groups,ischemia-reperfusion group (Group I-R),ischemia 30 min and reperfusion 120 min without additional intervention; myocardial ischemic postconditioning group(Group Post),after 30 min ischemia,the rats were comprised 3 cycles of 10 seconds reperfusion followed by 10 seconds ischemia,and then the rats were reperfused 120 min; myocardial ischemic postconditioning+AG490 (JAK2-STAT3 pathway inhibitor) group (Group Post+ AG490),rats were treated with AG490 5 minutes before reperfusion,followed by myocardial ischemic postconditioning and 120 min reperfusion. The myocardial infarct size was measured by TTC staining. Apoptotic index of cardiomyocyte was detected by TUNEL. Results:Myocardial infarct size and myocardium apoptotic index were significantly reduced in Group Post compared to those in Group I-R (P0.05). AG490 inhibited cardioprotective effect of ischemic postconditioning. Conclusion:Ischemic postconditioning provides potent cardioprotective effect. JAK2-STAT3 pathway mediates the cardioprotective effects of ischemic postconditioning.