缺血预处理对离体缺血心脏跳动时间影响的实验研究

The effect of ischemic preconditioning on isolated heart beat during ischemia

目的探讨缺血预处理对心肌缺血耐受的影响。方法将28只SD大鼠随机分为缺血预处理组和对照组,每组14只。两组大鼠复制离体心脏灌注动物模型,缺血预处理组采用5min缺血、10min灌注,反复3次;对照组大鼠常温灌注45min,2组大鼠均心脏常温缺血30min。测定2组大鼠心脏缺血后跳动时间,于缺血前和缺血30min测定心肌ATP含量、Na+-K+-ATP酶活性。结果缺血预处理组心脏缺血后跳动时间较对照组明显延长[(14.3±3.6)minvs.(9.5±2.5)min,P<0.05],缺血后心肌ATP含量低于对照组[(275±43)nmol/gvs.(358±65)nmol/g,P<0.05],但缺血后2组间Na+-K+-ATP酶活性的差异无统计学意义。结论缺血预处理能提高心肌能量利用能力,延长缺血后心脏缺血跳动时间。

Objective To investigate the effect of ischemic preconditioning on myocardium during ischemia. Methods Preconditioning was accomplished by three 5-minute global ischemia separated by 10 rain intervals of reperfu- sion. Then 30 min ischemia was followed. Beating time during ischemia was investigated, before and at the end of ischemi- a. Ventricular muscle samples were taken to determine ATP and Na＋-K＋-ATPase activity. Results Isolated heart beating time during ischemia in the preconditioning group was longer and the myocardial ATP was more depleted during prolonged ischemia in the preconditioning group than in the control group （P 〈 0.05）. Na＋-K＋-ATPase activity during ischemia be- tween the two groups was not significantly different （P 〉 0.05）. Conclusions Preconditioning enhances the myocardial a- bility to tolerate ischemia and energy utilization. Ischemic preconditioning may prolong isolated heart beating during is- chemia.