Influences of endothelin-1 on apoptosis of hypoxia/reoxygenation myocardiocytes

AIM To explore the effects of endothelin-1 at different administrative timing on apoptosis and cell injury induced by hypoxia/reoxygenation.METHODS Primarily cultured neonatal rat cardiomyctes were treated with 950 ml/L N2-50 ml/L CO2 mixture to establish hypoxia/reoxygenation model. Flow cytometry and Hoechst 33258 stain were performed to determine the apoptotic rates of cardiomyocytes.A domestic kit was used to determine the activity of lactate dehydrogenase(LDH).RESULTS Cell viability values,apoptotic rates and lactate dehydrogenase(LDH) activity of cells with 24 h ET-1 treatment before hypoxia increased,lowered and decreased respectively compared with those in hypoxia/reoxygenation group(HR).ET-1 treatment during hypoxia depressed the cell viability,raised apoptotic rate and LDH release.ET-1 treatment during reoxygenation had no effects on these values.CONCLUSION ET-1 pretreatment has protective effects on cardiomyocytes from hypoxia/reoxygenation.However,ET-1 during hypoxia aggravates the injury of cardiomyocytes induced by hypoxia/reoxygenation.