等长收缩训练促进犬慢性缺血心肌侧支动脉生成的研究

Isometric exercise training stimulates coronary arteriogenesis in canine chronic ischemic myocardium

目的:观察等长收缩训练对犬慢性缺血心肌侧支动脉生成的影响。方法:应用Ameroid缩窄器制备犬慢性冠状动脉狭窄模型,造模成功后,将模型动物随机分为3组:假手术组(SO,n=6),单纯心肌缺血组(OMI,n=6),被动等长收缩训练组(PIE,n=6)。SO组进行开胸手术,不进行慢性心肌缺血造模,也不给予任何缺血刺激和运动训练,安静笼养;OMI组手术进行慢性心肌缺血造模,不进行任何运动训练;PIE组手术进行慢性心肌缺血造模,关胸后休息1周后开始被动等长收缩训练,采用100%最大强度训练1min,休息1min,每日重复20次,每周训练5天,训练时程为6w。实验终点时,所有模型犬采用心脏SPECT成像测定心肌缺血区域血流灌注;微球技术检测缺血心肌冠状动脉侧支循环血流量;免疫组化法测定犬缺血心肌组织单核细胞、内皮细胞及平滑肌细胞数量,小动脉密度。结果:6周PIE后,OMI组的静息血流灌注心肌节段总评分最高,PIE组的值高于SO组。冠状动脉侧支循环血流量(MBF)在PIE组显著高于OMI组及SO组。PIE组的内皮细胞数量、单核细胞数量、平滑肌细胞数量均显著高于其他各组。通过相关性分析发现,小动脉密度与MBF呈正相关;内皮细胞数量、平滑肌细胞数量、单核细胞数量均与小动脉密度呈正相关。结论:等长收缩训练可以促进远隔缺血心肌侧支动脉生成,改善侧支循环血流,实现"生物搭桥"。

Objective： To investigate the effects of active isometric exercise training on coronary arteriogenesis in canine model of chronic ischemic myocardium.Method： An Ameroid constrictor was placed around the left anterior descending branch of the left coronary artery in healthy adult male canine. The animals were divided into three groups： sham-operated group（SO）（n=6）, only myocardial ischaemia group（OMI）（n=6）, passive isometric exercise training group（PIE）（n=6）. Canine in the PIE group performed passive isometric exercises for 6 weeks, whereas canine in the SO group and OMI group remained sedentary. At the endpoint, SPECT imaging was used to evaluate myocardial perfusion.Myocardial blood flow of ischemic area was measured by colored microspheres. The expression of arteriolar density, the proliferation of mononuclear phagocyte, smooth muscle cells and endothelial cells were measuredby immunohistochemical analysis.Result： Compared with the other two groups, SO group had the lowest summed rest score. The score in the PIE group was lower than that in the OMI group. The MBF in the PIE group was markedly higher than those in the OMI and SO groups. The arteriolar density in the PIE training group was the highest among the three groups. EC number, SMC number and MC number in the PIE group was higher than those in the OMI and SO groups. The collateral blood flow was correlated with the arteriolar density. The arteriolar density was correlated with the EC count, SMC count and MP count.Conclusion： Active isometric exercise could stimulate coronary arteriogenesis in the canine model of chronic myocardial ischemia, increase the blood perfusion in ischemic myocardium.