银杏叶提取物后处理对兔心肌缺血-再灌注损伤的影响

Effects of Gingkgo biloba leaf extract postconditioning on myocardial ischemia reperfusion injury in rabbit

目的探讨银杏叶提取物(EGb761)后处理对兔心肌缺血-再灌注损伤的保护作用。方法 32只兔随机分为假手术组(S组,开胸后仅行左冠脉套线而不阻断160 min)、缺血-再灌注组(IR组,行左冠状动脉前降支阻断40 min,再灌注120 min)、缺血后处理组(IPC组,结扎冠状动脉前降支40 min,再通30 s,结扎30 s,重复3次,再灌注120 min)和EGb761后处理组(E组,开放左冠状动脉即刻1 min内予以静脉推注EGb761 100mg/kg,再灌注120 min)。分别于左冠前降支阻断前20 min(T1)、左冠前降支阻断20 min(T2)、左冠前降支阻断40 min(T3)、心肌再灌注1h(T4)和心肌再灌注2 h(T5)抽取颈内动脉血测定血清肌钙蛋白(IcTnI)含量。再灌注末抽血离心测定超氧化物歧化酶(SOD)、丙二醛(MDA),测定梗死面积。结果和IR组相比,IPC组和E组再灌注各个时间点cTnI均降低(P<0.05);IPC组和E组梗死面积均小于IR组(P<0.05);IPC组和E组血清中SOD的活性高于IR组,MDA的含量低于IR组(P<0.05)。结论银杏叶提取物后处理具有类似缺血后处理的心肌保护作用,其机制可能是通过减少氧自由基的生成,增强心肌抗氧化能力有关。

【Objective】 To investigate the protective effection of Gingkgo biloba leaf extract（EGb761） postcondi-tioning on myocardial ischemia-reperfusion injury（I/R） in rabbit.【Methods】Thirty-two New Zealand male white rabbits were randomly assigned to Sham group,I/R group,ischemia group and EGb761 group.Sham group was per-fused for 160 min,group I/R was underwent 40 min ischemia and 120min reperfusion;group ischemia was under-went three cycles of 30 seconds reperfusion and 30 seconds LAD re-occlusion immediately after 40 min ischemia and before 120 min reperfusion,and group EGb761 was given EGb761 100 mg/kg immediately after 40 min ischemi-a in 1 min and before 120 min reperfusion.Blood samples were taken from arterial line at 20 min before occlusion（T1）,20 min after occlusion（T2）,40 min after occlusion（T3）,1 h after reperfusion（T4） and 2 h after reperfusion（T5） for determination of plasma cTnI.At the end of the reperfusion,infarct size（IS） and area at risk（AAR） were defined by Evans and TTC staining.Plasma superoxide dismutase（SOD） activity and malondialdhyde（MDA） level were deter-mined at the end of reperfusion.【Results】The levels of cTnI were significantly less during reperfusion in the two postconditioning groups than those in I/R group.The plasma MDA content was significantly lower and SOD activity as significantly higher in the two postconditioning groups than those in I/R group,but there was no difference be-tween the two postconditioning groups.【Conclusion】EGb761 postconditioning is as effective as ischemic postcondi-tioning in protecting myocardium against I/R injury in rabbits.Decrease in oxygen free radicals and increase in an-tioxidant activity may be involved.