[The effect of hypoxic preconditioning on myocardium energy metabolism].

AIM AND METHODS: To evaluate the protective effects of hypoxic preconditioning (HPC) on myocardial energy metabolism, Langendorff-perfused hearts, exposed to HPC, were subjected to hypoxia/reoxygenation (5/10 min). 31P NMR was used to sequentially follow the time courses of high energy phosphates (HEP) contents and intracellular pH (pHi) of the rat myocardium. RESULTS: The Contents of Phosphocreatine (PCr), Adenosine Triphosphate (ATP) and the PCr/Pi (inorganic phosphate) ratios decreased during 30 min hypoxia, but the reduction was slower for the HPC group compared with Control. Reoxygenation induced recovery of myocardial HEP in both groups, HPC enhanced t he recovery especially in initial stage o f reoxygenation. However, pHi change was not significant for HPC group in this experiment. CONCLUSION: HPC improves the myocardial energy metabolism level during prolonged hypoxia and subsequent reoxygenation and protects myocardium against hypoxia/reoxygenation injury.