低氧预处理对低氧／复氧心肌能量代谢的作用

目的：研究低氧预处理（HPC）对心肌的保护作用,方法：借助^31P－NMR图谱技术,在模拟Langendorff离体灌流大鼠心脏的正常生理条件下,跟踪心肌高能磷酸化合物含量的动态变化。结果：在30min低氧期,PCr、ATP相对含量及PCr/Pi值逐渐减小,但HPC组减小的速度比对照组慢;而在复氧期,HPC组能提高心肌高能磷酸化合物含量的恢复程度,特别是复氧初期,HPC组PCr 、ATP相对含量及PCr/Pi值立即有了恢复;在本实验中,HPC对pHi的改善不显著。结论：HPC能降低后续长时间低氧及复氧阶段的心肌能量代谢,对心肌的低氧／复氧损伤具有保护作用。

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/reoxygrnation(5/10 min). 31 P 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 the recovery especially in initial stage of 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.