Effect of heme oxygenase-1 on hypoxia-reoxygenation injury in cultured neonatal rat cardiomyocytes

Abstract

Objective To investigate the effect of heme oxygenase-1 (HO-1) on hypoxia-reoxygenation (H/R) injury in cultured neonatal rat cardiomyocytes. Methods Primary cultured neonatal rat cardiomyocytes were randomly divided into4 groups: Ⅰ control group (group C), Ⅱ H/R group, Ⅲ hemin group and Ⅳ hemin+zinc protoporphyrin (ZnPP) group. In group H/R, the cardiomyocytes were exposed to 2 h of hypoxia followed by 6 h of reoxygenation. Hemin was added to the culture medium with a final concentration of 20 μmol/L 24 h before hypoxia and immediately before hypoxia in group hemin. Hemin and ZnPP were added to the culture medium with final concentrations of 20 μmol/L 24 h before hypoxia and immediately before hypoxia in group Henin + ZnPP. The cells were incubated in 35 mm culture dishes (2 ml in each dish) and 50 ml culture flasks (3 ml in each flask)(45 dishes and 3 flasks in each group). The HO-1 expression, cell survival rate, LDH activity, malondialdehyde (MDA) level and superoxide dismutase (SOD) activity were detected after the end of reoxygenation. Results Compared with group C, the LDH activity, MDA level and HO-1 expression were significantly increased, while the cell survival rate and SOD activity decreased in the other three groups ( P ＜ 0.05). Compared with group H/R,the LDH activity and MDA level were significantly decreased, while the HO-1 expression, cell survival rate and SOD activity increased in group hemin ( P ＜ 0.05 ), but no significant change was found in group hemin + ZnPP (P ＞0.05). H/R injury was obvious in group H/R and hemin + ZnPP, but was significantly attenuated in group hemin. Conclusion HO-1 can protect cardiomyocytes against H/R injury in neonatal rats. Key words: Heme oxygenase-1; Myocytes, cardiac; Cell hypoxia; Oxygen