The role of protein kinase C signal transduction in apoptosis of cardiomyocytes induced by hypoxia

Objective To investigate the roles of protein kinase C signal transduction in apoptosis of cardiomyocytes induced by hypoxia.Methods Cultured neonatal rat cardiomyocytes were randomly assigned to eight groups including control group, hypoxia for 6h group, hypoxia for 12 h group, hypoxia for 24 h group, PMA(Phorbol 12 myristate 13 acetata)10nM group, PMA 100nM group, CHE(chelerythrine)1μM group and CHE1mM group. In control group, cardiomyocytes were cultured under 95%O 2 and 5% CO 2;In PMA 10nM group and PMA 100nM group, cardiomyocytes were cultured for 24 h under 95%N 2 and 5% CO 2 after being preconditioned by PMA10nM or PMA 100nM respectively; cardiomyocytes were cultured for 24 h under 95%N 2 and 5% CO 2 after being preconditioned by CHE1μM or CHE1mM respectively in CHE 1μM group and CHE 1mM group. After culture was ended, apoptosis cells were measured by TUNEL label in individual cardiomyocyte, and viability was determined by trypan blue exclusion. Results Both apoptosis and necrosis were induced by hypoxia in cultured rat cardiomyocytes with a time dependent manner. Less apoptosis cells were induced by hypoxia in PMA 10nM group than in hypoxia for 24 h group( P 0.05), but in comparison with hypoxia for 24 h group, more apoptosis cells were induced in PMA 100nM group and CHE1μM group( P 0.05).Apart from control group, the cell viabilities of the other groups were not statistically significant. Conclusion Protein kinase C is involved in anti apoptosis signal in cardiomyocytes during hypoxia. The anti apoptosis signal and anti necrosis signal of PKC might be distinct during hypoxia.