Association between delayed cardioprotection of aged rat myocytes and activation of mitogen-activated protein kinase

Objective To study the cardioprotective effects of hypoxic preconditioning (HPC) on aged rat ventricular myocytes and the cellular mechanism of protec tion. Methods In the model of hypoxia/reoxygenation (H/R) of isolated ventricular myocytes of aged rat, the effects of HPC on aged rat ventricular myocytes against lethal H/R stimulated ischemia/reperfusion (I/R) injury 24 hours la ter and the changes of mitogen-activated protein kinase (MAPK) system were observed in the present study. Results HPC attenuated the lactate dehydrogenase (LDH) release and ATP depl etion in myocytes and increased the viability of myocytes. It was also foun d that MAPK and its down-stream kinase-S6 kinase were also activated after HPC. Conclusion There is delayed cardioprotection in cardiac myocytes of aged ra t and the cellular mechanism underlying might involve the activation of MAP K system.