等长收缩训练促进犬慢性心肌缺血侧支动脉生成的机制

目的:观察等长收缩训练对慢性心肌缺血犬血压、血管壁剪切力及血流灌注的影响,探索等长收缩训练促进缺血心肌侧支动脉生成的机制。方法:制备犬慢性冠状动脉狭窄模型,随机分为假手术组,单纯心肌缺血组,被动等长收缩训练组。实验终点时,所有犬在DSA检查后检测血管壁剪切力(wall shear stress,WSS)及记录收缩压、舒张压的数值,记为基础值;PIE组除了测定基础值外,还使用电刺激诱发IE运动,测定IE开始前30s、开始后30s及停止后30s的收缩压、舒张压及WSS的值。检测缺血心肌冠状动脉侧支循环血流量(collateral blood flow,CBF)、单核细胞(mononuclear phagocyte,MP)及平滑肌细胞(smooth muscle cell,SMC)的数量。结果:6周IE后:(1)WSS:实验终点经过DSA造影发现,PIE组WSS的基础数值最高(P<0.05)。PIE组实验犬在DSA造影过程中行IE运动不同时间点的WSS值相比较,IE开始后30s的WSS值最高(P<0.05)。(2)血压:实验终点时基础血压值相比较,SO组的SBP值最低(P<0.05);PIE组的DBP值最高(P<0.05)。PIE组实验犬在DSA造影过程中IE运动不同时间点的SBP、DBP相比较,IE开始后30s的SBP值最高(P<0.05)。(3)心肌局部血流量及细胞学检测:PIE组的CBF、平滑肌数量、单核细胞数量最高(P<0.05)。(6)相关性分析发现:WSS与CBF呈中度正相关;WSS与SMC呈高度正相关;WSS与MP呈高度正相关。实验终点时PIE组犬不同时间点的WSS与SBP、DBP的相关性分析发现,WSS与SBP呈高度正相关;WSS与DBP呈中度正相关。结论:等长收缩训练可以通过升高血压,提高血管壁剪切力水平从而促进缺血心肌血流灌注。

The effect of isometric exercise training on blood pressure, wall shear stress and myocardial blood flow in canine chronic ischemic myocardium

Objective: To investigate the effects of isometric exercise training on blood pressure,WSS and myocardial blood flow in canine 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 3 groups:sham-operated group,only myocardial ischaemia group,passive isometric exercise training group.At the endpoint,digital subtraction angiography and CFD were used to calculate the values of WSS and blood pressure was recorded.WSS and blood pressure were also measured before,during and after IE exercise in PIE group.Myocardial blood flow,mononuclear phagocyte,smooth muscle cells of ischemic area were measured.Result:(1)The CBF in PIE group was the highest among the four groups. SMC number in PIE group was the highest among the 3 groups.(2) The MP number in PIE group was the highest among the 3 groups.(3) The WSS value in the PIE group was the highest among the 3 groups. WSS value during IE was the highest compared to those before IE(P<0.05) and after IE(P<0.05). The SBP value during IE was the highest than those before IE(P<0.05) and after IE(P<0.05). The SBP in the SO group was the lowest among the 3 groups. The DBP in PIE group was the highest among the 3 groups. SBP during IE was the highest among those before IE(P<0.05) and after IE(P<0.05). DBP during IE was the highest than those before IE(P<0.05) and after IE(P<0.05).(10)Correlation analysis: The collateral blood flow was highly correlated with WSS. The SMC count and MP count were highly correlated with WSS. In the PIE group, the WSS was highly correlated with the SBP.The WSS value was moderately positive correlated with DBP.Conclusion: Isometric exercise could promote the blood perfusion in chronic coronary stenosis model by increasing blood pressure and enhancing wall shear stress. Compared with PIE, AIE was more effective.