系统性缺血预适应对心肌缺血再灌注损伤的保护作用

目的探讨系统性缺血预适应对缺血再灌注心肌是否具有早期保护作用。方法将24只新西兰大白兔随机分为单纯缺血再灌注组（I组）、经典缺血预适应组（IPC组）、系统性缺血预适应组（SIP组），每组8只。I组丝线结扎冠状动脉左前降支，缺血30rain，再灌注120min。IPC组冠状动脉左前降支缺血5min，再灌注10min，重复2次，后同I组。SIP组5min内从股动脉抽血，使平均动脉压降至50mmHg并维持10min，此后用5min把放出的血输回，后同I组。检测3组缺血前、缺血30min、再灌注30min、再灌注120min各时间点血清cTnI浓度、SOD活性及MDA、NO含量的变化。结果（1）缺血前各观察指标3组相比，差异均无统计学意义（P〉0．05）；（2）缺血30min，再灌注30、120min时点IPC、SIP组血清cTnI浓度、MDA含量明显低于I组（P〈0．05），IPC、SIP组血清SOD活性、NO含量明显高于1组（P〈0．05）；（3）SIP组较IPC组效果显著，但各指标2组比较，差异均无统计学意义（P〉0．05）。结论系统性缺血预适应对心脏缺血再灌注损伤具有早期保护作用，能明显减少心肌细胞坏死。

Effect of Systemic Ischemic Preconditioning on Myocardial Ischemia-reperfusion Injury

Objective To investigate whether transient systemic ischemia can precondition the heart against the ensuing myocardial ischemia-reperfusion injury. Methods 24 adult new zealand white rabbits Of either sex were randomly divided into 3 groups,8 rabbits in each：ischemia-reperfusion group （group I ）,classic IPC group （group IPC）,and systemic ischemic preconditioning （group SIP）. For group I ,the left anterio coronary（LAD） of each rabbit was occluded by suture silk for 30 min,followed by reperfusion for 120 min. For group IPC,5 min of LAD occlusion and 10 min of reperfusion were conducted twice, followed by the same procedures as were done in group I. For group SIP,SIP was induced by rapidly（5 min）withdrawing blood from femoral artery to keep the mean artery pressure at 50 mm Hg for 10 min,and then the withdrawn blood was transfused back in 5 min,followed by the same procedures as in group I . The index variance of serous troponin I （cTnI） concentration, superoxide dismutase （SOD） activity, malondialdehyde （MDA） ,NO level were measured respectively before ischemia, 30 minutes after ischemia, 30 min after reperfusion, and 120 min after reperfusion. Results （1）Before is chemia （pre-I）, there was no statistical significane of all the index among the three groups（P〉0.05）. （2）At the time of ischemia 30 min,reperfusion 30 min,reperfusion 120 rain,the index of serous troponin I（cTnI） concentration and malondialdehyde（MDA） level in SIP and IPC group were obviously lower than that in group I（P〈0.05）. Compared with group I,superoxide dismutase （SOD） activity and NO level were significantly higher in SIP and IPC group I（P〈0.05）. （3）The protective effect in SIP group was more remarkable than that in IPC group, but there was no statistical significance between them of all the index（P〉0.05）. Conclusion The systemic ischemic preconditioning （SIP） has an early protective effect on the myocardial isehemia-reperfusion injury and could decrease the