粒细胞集落刺激因子促进大鼠梗死心肌的血管新生

PROMOTING EFFECT OF GRANULOCYTO-COLONY STIMULATING FACTOR ON NEOVASCULARIZATION IN RATS WITH MYOCARDIAL INFARCTION

目的观察粒细胞集落刺激因子(granulocyto-colony stimulating factor,G-CSF)对骨髓中内皮前体细胞(endothelial progenitor cells,EPCs)的动员作用,以及对心肌梗死交界区组织VEGF及其受体Flk-1mRNA表达的影响,并观察梗死交界区毛细血管密度的改善程度。方法雄性Wistar大鼠36只,体重250～280g,随机分为对照组、心肌梗死组(心梗组)和G-CSF组。心梗组和G-CSF组采用冠状动脉左前降支结扎法制作心肌梗死模型后,分别腹腔注射生理盐水(0.3mL/d)和G-CSF[30μg/(kg?d)],连续5d;对照组开胸后直接关胸,不行任何处理。给药后第7天球后静脉采血,测定EPCs水平和VEGF、C反应蛋白(C-reaction protein,CRP)浓度;RT-PCR检测心肌梗死交界区VEGF及其受体Flk-1mRNA的丰度。第4周采用Ⅷ因子免疫组织化学染色检测心肌梗死交界区毛细血管密度,行HE染色和Masson染色观察组织形态学变化。结果心梗组外周血白细胞数、EPCs水平以及VEGF和CRP浓度均较对照组增加(P<0.05),G-CSF组外周血白细胞数、EPCs水平以及VEGF浓度较心梗组进一步增高(P<0.05),但CRP浓度较心梗组有所降低(P<0.05)。心梗组VEGF及其受体Flk-1mRNA表达丰度均较对照组增强(P<0.05),G-CSF组较心梗组进一步增强(P<0.05)。G-CSF组较心梗组及对照组有更多的淋巴细胞浸润及新生毛细血管形成。结论 G-CSF能够动员骨髓中的EPCs进入外周血并上调梗死交界区VEGF及其受体Flk-1mRNA的表达丰度,增加心肌梗死交界区毛细血管密度,具有促进心肌梗死大鼠血管新生的作用。

Objective To investigate the effects of granulocyto-colony stimulating factor （G-CSF） on the mobilization of endothelial progenitor cells （EPCs） in the rats with myocardial infarction （MI）, to observe the density of neovascularization and the mRNA expressions of vascular endothelial growth factor （VEGF） and its receptor （Flk-1） in the border area of MI. Methods Thirty-six adult male rats （weighing 250-280 g） were divided randomly into control group, MI group, and G-CSF group. In MI group and G-CSF group, the models of MI were established by left anterior descenting coronary artery ligation and were treated with intraperitoneal injection of saline （0.3 mL/d） or G-CSF [30 μg/（kg.d）] for 5 days. In control group, after open chest operation, chest was closed without treatment. The level of EPCs was surveyed and the plasma concentrations of VEGF and C-reaction protein （CRP） were measured at 7 days. The mRNA expressions of VEGF and its receptor Flk-1 in the border area of infarct myocardium were determined through RT-PCR. Results Compared with control group, the number of circulating white blood cell （WBC） and EPCs levels, and the serum concentrations of VEGF and CRP were all significantly increased in MI group and G-CSF group （P 〈 0.05）; when compared with MI group, the number of circulating WBC and EPCs levels, and the serum concentrations of VEGF were increased and the concentration of CRP was decreased in G-CSF group （P 〈 0.05）. Compared with control group, the mRNA expressions of VEGF and Flk-1, and the density of neovascularization in the border area of infarct myocardium were increased in MI group and G-CSF group, whereas those in G-CSF group were significantly augmented compared with MI group （P 〈 0.05）. Conclusion In the rats with MI, G-CSF could promote EPCs mobilization, increase the mRNA expressions of VEGF and Flk-1, and augment the density of neovascularization in the border area of infarct myocardium.