Abstract: Objective To investigate the protective effects of recombinant human erythropoietin（rhEPO）on rat myocardial ischemia-reperfusion（I/R）injury and the relationship with autophagy. Methods 60 SD rats were randomly divided into sham-operated group（sham group）, ischemia-reperfusion group（I/R group）, rhEPO treatment group（rhEPO group）, rhEPO + autophagy activator Rapamycin treatment group （rhEPO +Rap group）and Rapamycin treatment group （Rap group）. Myocardial ischemia- reperfusion（I/R）models were established, and hemodynamic indices（LVSP 、LVEDP、+dp/dtmax、-dp/dtmax）were monitored during the procedure. Serum creatine kinase (CK) , lactate dehydrogenase(LDH) of different groups were detected at the end of reperfusion. Myocardial infarct areas were measured by applying Evans blue and TTC staining respectively. The protein expressions of autophagy associated genes LC3 and Beclin1 in myocardium were identified by Western blot. Results Compared with sham group, I/R group showed weaker cardiac function，higher levels of serum CK、LDH and obvious myocardial infarct, LC3Ⅱ/ LC3Ⅰ, Beclin1 expressions were significantly increased（P < 0.01）. rhEPO treatment can significantly improve cardiac function, reduce the serum levels of CK and LDH, reduce the myocardial infarct area, and significantly decrease the expressions of LC3Ⅱ/ LC3Ⅰ, Beclin1（P < 0.01）. Autophagy activator rapamycin can weaken the effect of rhEPO .Conclusions rhEPO reduce autophagy plays an important role in the cardioprotection of rhEPO in rats model of myocardial ischemia- reperfusion injury.

Key words: myocardial ischemia- reperfusion, recombination human erythropoietin, autophagy