AIM:To investigate the myocardial protective effect of endometrial stem cell ( EnSC)-derived cyto-kine cocktail ( EdCC) on myocardial ischemic reperfusion injury and the MEK-ERK signaling pathway.METHODS: A mouse model of myocardial ischemic reperfusion injury was established.Infarct area, cell apoptosis, and expression of cleaved caspase-3 and phosphorylatied ERK1/2 were determined by TTC/Evans blue staining, TUNEL assay and Western blot, respectively.RESULTS:The mesenchymal characteristics were observed in the EnSCs with expressing CD90 and in absence of CD34 and CD45.EdCC contained (6 811 ±312) ng/g epidermal growth factor (EGF) protein.The phospho-rylation of ERK1/2 markedly increased after injection of EdCC, but was abolished by MEK1 inhibitor PD98059 ( 5 mg/kg) .EdCC decreased the infarct area and apoptotic cell number in the border zone and inhibited caspase-3 activation. However, the effects were abolished by MEK1 specific inhibitor PD98059.EGF did not decrease the infarct area, but the EGF receptor antagonist AG-1487 (6 mg/kg) partly abolished the myocardial protective effect of EdCC.CONCLUSION:EdCC protects the myocardium from ischemic reperfusion injury via activating MEK1-ERK signaling pathway, indicating an essential role in the transmission of stem cell therapy from the cell transplantation to cytokine based strategy.

Objective To improve the operation speed and reliability of the myocardial ischemia/reperfusion injury(I/R) model in mice.Methods The operative time and the survival rate of the three models were compared.The postoperative leukocyte count and serum IL-6 level were detected to evaluate the inflammatory response.The infarct size was assessed by TTC/Evans blue staining.The left ventricular end diastolic pressure and the pressure change rate were measured by a pressure catheter for the evaluation of cardiac function.Intraditional method,open chest surgery was performed to ligate and loose the left coronary artery(LCA)under the assistance of intubation and ventilation.In novel method,isoflurane was used for anesthesis,and then heart was squeezed out of the chest to ligate and loose LCA with a slipknot.In.overlapping line method,the heart was also squeezed out,but a square knot was performed to ligate LCA and a 2-0 nylon together,and then the nylon thread was drew out to loose LCA.Results Compared with traditional method,the novel method and overlapping line method had significant short operation time(P＜0.01 or P＜0.05),less white blood cell count and serum IL-6 concentration(P＜0.05) and higher mice survival rate(P＜0.01);compared with novel method,the overlapping line method further simplified the reperfusion procedure and decreased total procedure time(P＜0.01).There was no significant difference in cardiac infarct size and cardiac function by using the three methods(P＞0.05),but the overlapping line method had less coefficient of variation compared to novel method.Conclusion Compared with the novel method,the overlapping line method reduces the operation difficulty,shortens the operation time and improves the stability of I/R model.