Effects of hypoxia preconditioning and praeruptorin C preconditioning on phospholamban phosphorylation in rat cardiomyocytes

Abstract

Objetive To explore the effects of hypoxia preconditioning and praeruptorin C preconditioning on phospholamban(PLB)phosphorylation in rat cardiomyocytes.Methods The neonatal rat cardiomyocytes were randomly divided into 4 groups:control group,the hypoxia preconditioning(HP)group,the praeruptorin C preconditioning(PP)group and the hypoxia-reoxygenation(HR)group.Each group was untreated or treated with protein kinase A inhibitor H-89(H-89 negative/positive group).The value of LDH of cellular supernatant was determined by automatic biochemistry analyzer.The fluorescence intensity of intracellular Ca 2+ was detected with Fluo-3/AM loading by the flow cytometer.PLB phosphorylation was measured by radioautographic technique.Results Compared with the control group,the value of LDH and the fluorescence intensity of intracellular Ca 2+ were significantly higher in HR group(P0.05),but there was no significant difference between the HP group and the control group(P0.05).Compared with control group,the value of PLB phosphorylation in HP and PP groups increased by 15.6% and by 16.8%(P0.05),while the value in HR group significantly decreased by 29.3%(P0.05).The value of phosphorylation in groups unreated with H-89 was significantly higher than that in the groups treated with H-89(P0.05).Conclusions Cardioprotection induced by hypoxia preconditioning and praeruptorin C preconditioning against hypoxia-reoxygenation injury may be related with upregulating PLB phosphorylation.