兔心肌梗塞模型制备方法的改进及其在MRI中的应用

Improvement of Myocardial Infarction Model in Rabbit and Its Application in MRI Research

目的 对兔心肌缺血的模型制备方法进行改进 ,并探讨其在 MRI诊断研究中的价值。方法 分别采用高位结扎左冠状动脉前降支 (L AD)和同时低位结扎 L AD及左冠状动脉旋支 (L Cx)建立兔心肌梗塞模型 ,并在术后行 MRI检查 ,对取材后心肌标本行氯化三苯四氮唑 (TTC)及病理检查。结果 1L AD组 2 0 % (5 / 2 5 )发生心室颤动导致死亡 ,L AD +L Cx组无一例发生室颤死亡。 2 L AD组 EKG改变明显者占 5 6 % (14 / 2 5 ) ,其中 2 1.4 3% (3/14 )在即刻就有 EKG明显改变 ,并在 30分钟后恢复正常 ;EKG改变不明显者占 4 4 % (11/ 2 5 ) ;L AD +L Cx组 10 0 %有 EKG明显改变 ,且 30分钟后亦无明显恢复。 3L AD组心肌梗塞范围较小 ,并均限于左室前壁 ,室间隔前部损害 ;而 L AD+L Cx组心肌梗塞范围较大 ,且累及左室前壁及侧壁 ,无一例有室间隔前部损害。4 L AD组中有 30 % (6 / 2 0 )不能显示小灶缺血局部心肌运动降低 ,16 .6 7% (3/ 18)无法分辨早期小梗塞灶的 MRI信号变化 ;而 L AD+L Cx组均能显示缺血局部心肌运动降低及梗塞灶早期的 MRI信号变化。结论 低位结扎兔心 L AD+L Cx,手术死亡率低 ,EKG改变明显 ,梗塞面积较大 ,是 MRI研究中一种较理想的心肌缺血动物模型制备方法。

Objective To improve the rabbit model of myocardial infarction, and to evaluate the value of the model in MRI research. Methods Two approaches were used to prepare the animal model: ①The anterior descending branches of the left coronary artery (LAD) were ligated, ②The LAD and the left circumflex branch of the left coronary artery (LCx) were ligated at low position simultaneously. The MRI was performed after the operation. The samples of myocardium were stained in TTC and HE to detect the pathological changes. Results ① Twenty percent (5/25) of rabbits in the LAD group died due to ventricular fibrillation, while no rabbit died in the LAD+LCx group. ② Fifty six percent (14/25) of rabbits in the LAD group experienced EKG changes after operation, but three of them recovered in 30 minutes. All (30/30) in the LAD+LCx group experienced EKG changes without recovery. ③ The infarction was limited in the anterior walls in LAD group, with seven only occurred in the medial anterior wall and five involving the anterior ventricul septa. The infaction of both anterior and lateral walls happened in the LAD+LCx group without the involvement of the anterior ventricul septa. ④ The dysfunction of the ischemic myocardium was not revealed in 30%(6/20) rabbitsin the LAD group at the early stage. The signal changes of small infarct could not be detected by the MRI in 16.67%(3/18) rabbits in the LAD group at the early stage. The signal changes of small infarct could not be detected by the MRI in 16.67% (3/18) in the LAD group. But the dysfunction of the ischemic myocardium and the signal changes of small in farct were found at the early in the LAD+LCx group. Conclusion Ligating the LAD and LCx in low position can produce an ideal model for the myocardial ischemia research in terms of the low death rate and the stable and large infarction areas.