Abstract: Objective To investigate the influence of erythropoietin in the metabolism of extracellular matrix after myocardial ischemia-reperfusion injury. Method The langendroff reperfusion system was applied to investigate the protect function of EPO on the ischemia-reperfusion condition in rats. The effects of EPO on extracellular matrix were observed by western blot and signal pathway blocker. The LVDP and infarction area were observed at the same time. Results: EPO significantly improved LVDP（19.8+0.2mmHg vs 35.9+0.2mmHg，IR group vs EPO+IR group，p<0.05）and decreased infarction area （35.26%+7.13% vs 62.70%+7.23% IR group vs EPO+IR group，p<0.05）. The MMPs expressions were significantly attenuated and Collagenase I/III were significantly enhanced by EPO(MMP2 53.2+2.6vs21.2+2.5; MMP9 57.6+3.1vs 19.2+2.6; IR组vs IR+EPO组, p<0.05 ；CollagenI 43.2+2.2vs11.4+2.3; CollagenIII 55.3+3.2vs 18.1+2.3; IR+EPO组vs IR组, p<0.05 ). This function can be inhibited by Mek-Erk inhibitor. Conclusion: EPO play a role in the metabolism of extracellular matrix by Mek-Erk signal pathway, which can protect the heart tissue from ischemia-reperfusion injury.

Key words: erythropoietin, extracellular matrix, ischemia－reperfusion injury