ABSTRACT
AIM: To observe the change of subunit of NADPH oxidation enzyme complex nox - 1 protein in cardiocyte hypoxia - reoxygenation injury and the role of cardiotrophin -1.METHODS: Cardiomyocytes from the hearts of 1 -3 d old neonatal rats were prepared by a modified method. Five groups were included in the study: control; hypoxia/ reoxygenation; hypoxia/reoxygenation + CT - 1; CT - 1 + hypoxia/reoxygenation + LY294002 (PIK3/Akt inhibitor) ; CT -1 + hypoxia/reoxygenation + PD98059 (ERK inhibitor) ; CT - 1 + hypoxia/reoxygenation + DMSO. The concentration of CT -1 was 10 μg/L. The survival rate of myocytes was evaluated by MTS method. Apoptosis, mitochondrial permeability transition pore ( △ψm) and reactive oxygen species ( ROS) were detected by flow cytometry. Nox - 1 protein was determined by Western blotting. RESULTS: Apoptosis of cardiomyocytes and the level of ROS (19.7% ±1.4% vs 2.1% ± 0.5% , 14.07% ± 1.25% vs 3.54% ± 0.86% , P < 0.05 ) increased markedly after hypoxia/reoxygenation, but cardio-myocyte survival rate and the level of△ψm (40.55% ±4.25% vs 86.28% ±7.15% , P <0.01) decreased significantly. The expression of nox - 1 protein was upregulated markedly. With CT - 1 intervention, cardiomyocyte survival rate increased markedly, apoptosis, both ROS and expression of nox - 1 protein reduced significantly. The level of△ψm increased obviously. The effect of CT - 1 was inhibited by LY294002.No significant effect was observed on cells survival in DMSO group, which confirmed that LY294002 was specifically involved in blocking the protective effect of CT - 1.CONCLUSION : The expression of subunit of NADPH oxidation enzyme complex nox - 1 protein is upregulated markedly in cardiocyte hypoxia - reoxygenation injury.CT - 1 protects cardiac cells against hypoxia - reoxygenation injury by downregulating the expression of nox -1 protein to decrease the level of ROS.