内皮祖细胞动员对兔生理性缺血训练促进远隔缺血心肌侧支生成的作用

Effects of mobilization of endothelial progenitor cells in physiological ischemic training on collateral circulation formation in rabbits with remote myocardial ischemia

目的:探讨血管内皮生长因子(VEGF)介导的内皮祖细胞(EPCs)动员在生理性缺血训练(PIT)促进远隔缺血心肌侧支循环生成过程中的作用。方法:42只兔进行可控性心肌缺血造模,造模成功后随机分入以下6组:假手术组、单纯生理性缺血训练组、单纯心肌缺血组、生理性缺血训练组、阿托伐他汀组、雷帕霉素组。生理性缺血训练共4周,每次3min,间隔5min,每周训练5d,每天训练3次。实验终点时,处死动物取材,进行实验室检测:ELISA法检测外周血中VEGF含量;Western blot法检测缺血心肌中VEGF表达;流式细胞术检测外周血和缺血心肌中EPCs数量;微球技术检测缺血心肌侧支循环血流量。结果:4周PIT后,VEGF含量在PIT组和PIT+组显著增加,与SO组、TO组和MI组相比,外周血和缺血心肌中VEGF含量在PIT组显著增加,结果具有显著性意义。PIT+组的EPCs数量在外周血和缺血心肌中均显著高于其他各组,PIT组与其他各组相比,外周血EPCs数量的差异同样具有显著性意义。冠状动脉侧支循环血流量(CCBF)和CCBF/冠状动脉血流量(CBF)在PIT+组和PIT组显著高于SO组、TO组和MI组。PIT-组的各项指标与SO组和TO组相比,差异均无显著性意义。EPCs数量的增加最高有43%可以被VEGF含量的增加解释,CCBF和CCBF/CBF的增加最高有90%可以被EPCs数量的增加解释。结论:PIT可促进EPCs动员,通过其远隔效应归巢到缺血心肌生成侧支循环,改善冠脉血流,最终实现"生物搭桥";通过促进和抑制EPCs,证实EPCs在PIT介导的缺血心肌侧支循环生成过程中具有重要作用。

To investigate the effects of physiological ischemic training（PIT） and the important role of endothe- lial progenitor cells（EPCs） mediated by vascular endothelial growth factor（VEGF） on the protection of remote ischemic myocardium induced by PIT in the rabbit model of controllable myocardial ischemia.Method： Forty-two rabbits were randomized into six groups： sham-operated （SO）, training only （TO）, myocardi- al ischemia （MI）, physiological ischemic training （PIT）, EPC promotor （PIT＋）, and EPC inhibitor （PIT-） group. At the endpoint, VEGF protein and EPCs were measured in plasma and myocardium. Coronary blood flow （CBF） and coronary collateral blood flow （CCBF） were also determined. All groups were compared using non- parametric statistics and associations between agents explored with fractional polynomials regression.Result： VEGF protein levels were the highest in PIT＋ and PIT groups. PIT group did differ significantly from SO, TO, MI, and PIT- groups regarding plasma VEGF protein levels as well as protein levels in myocardium. EPCs were the highest in PIT＋ group followed by PIT. PIT group did differ significantly from SO, TO, MI, and PIT- groups regarding plasma EPCs. CCBF and CCBF/CBF increased significantly in PIT＋ and PIT groups as compared to controls. VEGF explained up to 43% of variance in EPCs. EPCs explained up to 90% of variance in CCBF and CCBF/CBF. Conclusion： PIT can improve revascularization via VEGF-mediated mobilization of EPCs and may be a new approach in the treatment of patients with coronary heart disease（CHD）.