[The anti-apoptosis effect of erythropoietin on neonatal rat cardiocytes during hypoxia/reoxygenation injury and its possible mechanism].

ABSTRACT

OBJECTIVE: To investigate the anti-apoptosis effect of erythropoietin (EPO) on myocardial cells after hypoxia/reoxygenation in vitro, and the relationship among protein kinase C (PKC), the mitochondrial ATP-sensitive potassium (mitoKATP) channel and EPO in the anti-apoptotic signaling pathways. METHODS: Cardiocytes were harvested from neonatal rats and cultured. Cultured myocardial cells were divided into the control group, the hypoxia/reoxygenation group, the EPO group and the chelerythrine group, and a hypoxia/reoxygenation model of cardiocytes was reproduced. Apoptosis rate was assayed by flow cytometry. Flavoprotein fluorescence was scanned by confocal laser microscope to assess the mitoKATP channel activity. RESULTS: Apoptosis rate was significantly higher in hypoxia/reoxygenation group than that of control group [(42.56+/-8.00)% vs. (17.88+/-2.00)%, P<0.05]. There was no statistically significant difference in flavoprotein fluorescence between this group and the control group [(0.278+/-0.170)x10(-2) vs. (0.149+/-0.050)x10(-2), P>0.05]. Myocardial cell apoptosis rate in EPO group was lower than that in hypoxia/reoxygenation group [(22.73+/-5.00)% vs. (42.56+/-8.00)%, P<0.05], and flavoprotein fluorescence intensity was significantly enhanced when compared with hypoxia/reoxygenation group [(2.201+/-1.090)x10(-2) vs. (0.278+/-0.170)x10(-2), P<0.01]. However, when chelerythrine was added, the anti-apoptosis effect of EPO was blocked, and the intensity of cardiocytes flavoprotein fluorescence was decreased [the apoptosis rate was (46.72+/-17.00)% and the flavoprotein fluorescence intensity was (0.986+/-0.320)x10(-2) ]. When compared with EPO group there was statistically significant difference (P<0.01 and P<0.05). CONCLUSION: Myocardial cell apoptosis occurs in hypoxia/reoxygenation injury, and EPO can protect rat cardiomyocytes from hypoxia/reoxygenation induced apoptosis. The protective effect is partly associated with the PKC/mitoKATP pathway.