犬重度心肌挫伤后冠脉血流储备改变的实验研究

Experimental study on change of coronary reserve in dogs with severe myocardial contusion

目的制备一种适合于临床研究所用的重度心肌挫伤(MC)动物模型,观察心肌挫伤后早期冠脉血流动力学的改变。方法选取杂种犬10只,3%戊巴比妥钠静脉麻醉,采用BIM-Ⅱ型水平撞击机制成MC模型。于伤前,伤后4、8h测量左冠状动脉舒张期最大峰值血流速度(PDV)并计算冠状动脉血流储备(CFR)。常规病理组织活检及TTC染色验证心肌损伤的程度。结果致伤前其CFR为3.30±0.27,伤后其CFR持续降低,伤后4、8h分别为2.07±0.33、1.82±0.34,与伤前相比差异有统计学意义(P<0.01),而伤后8h与4h相比,其CFR虽继续降低,但差异无统计学意义(P>0.05)。结论犬重度MC后冠脉血流储备降低,而冠脉血流动力学的紊乱可能是造成犬重度MC后心肌继发性缺血、坏死的又一原因。

Objective To establish an animal model of severe myocardial contusion （MC） that is practically useful for clinical studies,and to investigate the change of coronary reserve in dogs with severe myocardial contusion after MC. Methods Ten dogs were selected and anaesthetized with 3% pentobarbitorium sodium intravenous injection,and then impacted by BIM- Ⅱ biological impact machine for the establishment of MC. Peak velocity during diastole（PDV） were measured at time points as before wounding,4h and 8h after wounding. Coronary flow reserve（CFR） was assessed as the ratio of PDV. Conventional and stressed echocardiography were used for observing segmental abnormal ventricular wall motions, and these results were finally compared with pathological TTC staining. Results CFR of dogs presented a continuous decrease after wounding（P〈0. 01）. CFR before wounding was 3.30±0.27,CFR at 4h after wounding was 2.07±0.33 and CFR at 8h after wounding was 1.82±0.34. Though the CFR at 8h after wounding was lower than CFR at 4h after wounding,but it had no difference（P〉0.05）. Conclusion CFR of severe myocardial contusion of dogs decreases siginificantly. And then disturbance of the coronary blood flow might be an important reason inducing secondary myocardial ischaemia and necrosis after MC.