Comparison of hypoxia and hypoxia-reoxygenation induced cardiomyocytes apoptosis

AIM: To compare hypoxia and hypoxia reoxygenation induced apoptosis of cardiomyocytes and to investigate the role of apoptosis in cardiomyocytes injury caused by hypoxia/reoxygenation. METHODS: Cultured neonatal rat cardiomyocytes were divided into two groups.Both groups were cultured in an incubator of 950 ml/L N 2 and 50 ml/L CO 2 for 16, 32 and 48 h. Cells of one group were put into normal incubation for 6 h after hypoxia to form the cell models of hypoxia reoxygenation injury. Morphological changes in apoptotic cardiomyocytes were measured by TUNEL staining. Apoptosis rates were measured by flow cytometer. RESULTS: Positive cells were detected by TUNEL staining. Apoptotis rates of cardiomyocytes measured by flow cytometer after hypoxia for 16,32 and 48 h were (2.9±0.5)%,(6.2±0.8)% and (26.6±3 0)% respectively.The apoptosis rates of cells undergoing hypoxia for 16,32 and 48 h followed by reoxygenation for 6 h were (5.5±0.7)%,(11.0±1.1)% and (14.2±1.6)% respectively. CONCLUSION: The apoptosis rates of cardiomyocytes increased with time of hypoxia.Reoxygenation could worsen cardiomyocytes injury,as compared with hypoxia.