缺血后处理对大鼠移植心脏心肌缺血再灌注损伤不同时相的保护作用

目的探讨缺血后处理对大鼠移植心脏心肌缺血再灌注损伤不同时相的保护作用。方法建立近交系Lewis大鼠颈部异位心脏移植左心做功模型,受体大鼠存活2d后,随机分为3组:缺血再灌注组:结扎移植心脏冠状动脉左前降支30 min后再灌注3h、6h、12h、24h、2d、4d及7d,每个时相点8只受体鼠;缺血后处理组:移植心脏缺血30 min,在再灌注前1 min给予再通10秒,阻断10秒,连续3个循环。每个时相点8只受体鼠;假手术组:穿线做套环,但不收紧结扎线。分别比较再灌注结束后大鼠血清肌酸激酶同工酶MB(CK-MB)值、移植心脏心肌细胞凋亡指数和梗死范围。结果在再灌注时间3h、6h、12h、24h、2d、4d 6个时相点,缺血再灌注组与缺血后处理组血清CK-MB均值对应比较,差异均有统计学意义(P均0.05),均明显高于假手术组CK-MB值(P均0.05)。再灌注6h时,缺血后处理组CKMB峰值较缺血再灌注组明显降低[(34.73±8.83)U/L vs.(52.58±10.05)U/L,P0.01]。在再灌注时间3h、6h、12h、24h、2d、4d、7d 7个时相点,缺血后处理组心肌细胞凋亡指数及心肌梗死范围均低于缺血再灌注组,差异均有统计学意义(P均0.05),心肌细胞凋亡指数均高于假手术组(P均0.05)。结论缺血后处理在大鼠移植心脏心肌缺血再灌注3h~7d内能降低血清CK-MB峰值,减少心肌细胞凋亡和心肌梗死范围。

Protective effect of ischemic postconditioning on myocardial ischemia-reperfusion in rats with cardiac transplantation at different phases

Objective To investigate the protective effect of ischemic postconditioning on myocardial ischemia-reperfusion in rats with cardiac transplantation at different phases. Methods The model of cervical heterotopic heart transplantation （left heart work） was established in inbred line Lewis rats. After survived for 2 d, the rats were divided into ischemia-reperfusion group （each n=8 at 7 phases：3 h, 6 h, 12 h, 24 h, 2 d, 4 d and 7 d）, ischemic postconditioning group （each n=8 at the same 7 phases as above mentioned phases） and sham-operation group （n=8）. The value of serum CK-MB, and index of myocardial apoptosis and area of myocardial infarction of transplanted heart were compared after reperfusion. Results At 6 phases of 3 h, 6 h, 12 h, 24 h, 2 d and 4 d, the difference in average value of CK-MB had statistical significance between ischemia-reperfusion group and ischemic postconditioning group （all P〈0.05）. The value of CK-MB was significantly higher in ischemia-reperfusion group and ischemic postconditioning group than that in sham-operation group （all P〈0.05）. At phase of 6 h, the peak value of CK-MB was significantly lower in ischemic postconditioning group than that in ischemia-reperfusion group [（34.73±8.83） U/L vs. （52.58±10.05） U/L, P〈0.01]. At 7 phases of 3 h, 6 h, 12 h, 24 h, 2 d, 4 d and 7 d, the difference in the index of myocardial apoptosis and area of myocardial infarction had statistical significance between ischemia-reperfusion group and ischemic postconditioning group （all P〈0.05）. The index of myocardial apoptosis was higher in ischemia-reperfusion group and ischemic postconditioning group than that in sham-operation group （all P〈0.05）. Conclusion Ischemic postconditioning can reduce the peak value of serum CK-MB, myocardial apoptosis and area of myocardial infarction in rats with heart transplantation within 3 h to 7 d after myocardial ischemia-reperfusion.