缺血后适应心肌线粒体能量代谢研究

目的研究缺血后适应心肌线粒体能量代谢特点。方法以Langendofff离体心脏灌注系统构建缺血后适应大鼠模型，随机分为对照组．再灌注组和后适应组，每组16只。平衡20min后，对照组灌注60min;再灌注组停灌30min，再灌注30min；后适应组停灌30min之后，循环6次再灌注10s，停灌10s，再灌注28min。记录心率和冠状动脉流量。冉灌注末取心肌．用高效液相色谱法测定高能磷酸化合物三磷腺苷、二磷腺苷和一磷腺苷含量；用差速离心法提取心肌线粒体，用氧电极法测定线粒体3态呼吸、4态呼吸和线粒体呼吸控制率。结果与再灌注组比较，后适应组明显提高再灌注末的心率和冠状动脉流量，明显提高心肌内二磷腺苷和一磷腺苷含量，三磷腺苷在各组差异无统计学意义。线粒体3态呼吸和线粒体呼吸控制率改善。结论心肌线粒体能量代谢改善，是缺血后适应心肌保护的可能机制之一。

Experimental study on mitochondrial energy metabolism in ischemia postconditioning myocardium

Objectives To investigate the effectives of postconditioning in mitochondrial energy metabolism in ischemia-reperfusion myocardium. Methods Isolated langendorff heart model was established. Forty-eight male SD rats were divided into 3 groups randomly： sham operation group （S group）, ischemia reperfusion group （ IR group） and ischemia postconditioning group （P group） . After 20 minutes K-H perfusion for equilibration, the S group underwent 60 perfusion with 37℃ K-H solution. The IR group underwent 30 minutes ischemia and the reperfusion 30 minutes. The P group underwent 30 minutes, followed 6 cycles including 10 seconds reperfusion added 10 seconds ischemia and the reperfusion 28 minutes. The heart rate and the coronary flow at the end of equilibration and the reperfusion were recorded. At the end of experiment, HPLC was used to evaluate the content of ATP, ADP and AMP. Mitochondria were isolated with different centrifugations, the Clark electrodes were used to test the mitochondrial T3, T4 and RCR. Results Compared with IR group, the heart rate and the coronary flow was improved at the end of reperfusion in P group. There was no difference in 3 groups of ATP content in myocardium. However the content of ADP and AMP in P group were obviously elevated as compared with IR group. T3 and RCR were higher in P group than those in IR group. There was no difference in 3 groups of T4. Conclusions Ischemia postconditioning may provide protection by improving the mitochondrial energy metabolism in myocardium.