缺血后适应联用粒细胞集落刺激因子对心肌急性缺血再灌注损伤的保护作用

Cardioprotective effects of combining ischemic postconditioning with granulocyte-colony stimulating factor on acute myocardial ischemia-reperfusion injury

目的:探讨联合应用缺血后适应(IP)及粒细胞集落刺激因子(G-CSF)对实验动物心肌急性缺血再灌注损伤的保护作用。方法:将新西兰兔结扎心脏左室支(LVA)后随机分为4组:缺血再灌注对照组(IR组),松结后直接再灌注;G-CSF组,松结并于术后12 h开始皮下注射G-CSF,连续5 d;IP组,缺血后先行IP再完全灌注;G-CSF+IP组,联合应用IP及G-CSF干预。术中监测心电图ST段改变,同时测定手术前后外周血白细胞数(WBC)、肌钙蛋白I(cTnI),于术后4周进行超声心动图检查,采用2,3,5-三苯基氯化四氮唑(tTTC)染色计算心肌梗死的面积,采用电子显微镜观察超微结构改变。结果:IP组的ST段回落明显优于IR组;G-CSF组的WBC较IR组明显增高;IP、G-CSF及G-CSF+IP组的术后7 d cTnI含量均显著低于IR组;同时IP、G-CSF及G-CSF+IP组的心功能均优于IR组,其中G-CSF+IP组最好;TTC染色表明IP、G-CSF组梗死心肌面积均明显低于IR组,且G-CSF+IP组的梗死心肌面积最小,超微结构观察也显示G-CSF+IP组的心肌肌丝和线粒体损伤也明显减轻。结论:联合应用IP和G-CSF干预可减少实验动物心肌急性缺血再灌注损伤,减少线粒体损伤,并能促进心功能恢复,减轻心室重构。

Objective： To assess the efficacy and potential mechanisms of cardioprotection of ischemic postconditioning （IP） combined with granulocyte colony stimulating factors （G-CSF） against acute myocardial ischemia-reperfusion injury in New Zealand rabbits. Methods： After ischemia by left vertebral artery （LVA） occlusion for 30 rains, male New Zealand rabbits were randomly assigned into four groups （ n = 15 ）. Group 1 ： Ischemic-reperfusion alone （IR）group, thirty rains after LVA occlusion, reperfusion was immediately offered;Group 2： G-CSF group, animals were performed with the same operation as Group 1, and G-CSF at the dose of 10 μg · kg- 1 was daily simuhaneously subcutaneously injected for 5 days 12 h after reperfusion; Group 3 ： ischemic postconditioning （IP） group, after 30 rain ischemia and before reperfusion as Group 1, four episodes of 30 s reperfusion and 30 s occlusion were performed; Group 4： IP combined with G-CSF （IP ＋ G-CSF）group, both IP and G-CSF intervention were offered as Group 2 and Group 3. Electrocardiogram （ECG） monitoring was consecutively applied during the whole operation. Blood was drawn from femoral vein to evaluate white blood cell count （WBC） and cardiac troponin I（cTnI） contents before operation and 7 d after reperfusion. Four weeks after the operation, ultrasound cardiography was used to monitor left ventricular remodeling and function. Infarcted myocardial sizes were calculated with triphenyhetrazolium chloride staining. Morphologic changes of cardiac muscle tissues were observed with optical microscope and transmission electron microscope. Results： Compared with IR alone group, 1P group and IP ＋ G- CSF group had significantly lower ST- segment resolutions （ P 〈 0.05 ）. All groups treated with G-CSF showed more WBC 1 week later. The contents of cTnI after operation were significantly lower in G- CSF, IP and IP ＋ G- CSF groups, compared with IR group. Left ventricular ejection fraction, infarcted myocardial size and morphologic observation demonstrated that IP, G-CSF and IP ＋ G-CSF groups were significantly improved, compared with IR alone group. Among them, the magnitude of cardiac function improvement in IP ＋ G- CSF group was the highest. Conclusion： Combining IP with G- CSF is beneficial to the alleviation of acute myocardial ischemia-reperfusion injury.