Objective:To investigate the effects of recombinant human erythropoietin(rhEPO) on vascular endothelial cells apoptosis induced by tumor necrosis factor-alpha(TNF-α) and its possible mechanism.Methods:Human umbilical vein endothelial cells(HUVEC) were pretreated with rhEPO of different concentrations(12.5

25

50 IU/ml) before 50 ng/ml TNF-α treatment.The cell survival rate was measured by methyl thiazolyl tetrazolium(MTT) assay.The concentration of cytochrome C(CytC) in cytosol was analyzed using enzyme-linked immunosorbent assay(ELISA).The expression of Caspase-3 protein was examined by immunocytochemistry assay.The apoptosis index(AI) of HUVEC was detected by terminal dUTP nick-end 1abeling(TUNEL) method.The damage of DNA was evaluated using single cell gel electrophoresis(SCGE) assay.Results:rhEPO could significantly increase the cell survival rate

decrease the concentration of CytC

the relative content of Caspase-3

the AI of HUVEC and the damage of DNA in a concentration-dependent manner(all P<0.05).Correlation analysis showed that there was positive correlation between the concentration of CytC and AI(r=0.807

P<0.05).The concentration of CytC also had a positive correlation with the relative content of Caspase-3(r=0.583

P<0.05).Conclusion:rhEPO is a promising cell protector against apoptosis induced by TNF-α through interfering mitochondria-dependent apoptotic pathway.