大鼠急性心肌梗死模型建立的影响因素
The influencing factors for establishing a model of acute myocardial infarction in rats

摘要：目的 探讨在非人工通气条件下体质量、胸廓前后径与左右径的比例对大鼠急性心肌梗死(AMI)模型建立的影响以及梗死后左室功能的变化。 方法 按体质量将SD大鼠随机分为4组：A组30只(200～250g)，B组90只(250～300g)，C组60只(>300g)及D组20只(假手术组)。在非人工通气条件下，测量胸廓径线后，通过开胸结扎左冠状动脉前降支(LAD)建立心肌梗死模型；同时记录心电图变化，观察并测量AMI术后2周、4周的心室壁厚度、室壁运动情况及心脏功能的变化。术后2周开胸，观察心脏大体形态的改变；同时取心脏标本行HE染色并观察心肌组织超微结构。以上数据通过SPSS13.0统计软件进行分析。结果 ①经过30次实验后成功建立第1只大鼠AMI模型，100次实验后成模率逐渐稳定在83%左右；②与A组比较，B组、C组大鼠AMI成模率较高(P<0.05)，B组、C组成模率无差异(P>0.05)；③未发现大鼠胸廓的前后径与左右径的比值与成模率有相关性(P>0.05)；④术后2周开胸，见缺血区心肌颜色发白，室壁运动减弱。HE染色及电镜下可见心肌细胞丢失溶解，心肌结构不完整，肌丝断裂，大量纤维及胶原组织增生，线粒体染色变深，嵴模糊、水肿；⑤与D组相比，心梗组术后2周、4周的左室舒张末期内径(LVEDd)和左心室收缩末期内径(LVESd)增加(P<0.05)，左心室射血分数(EF值)和心率下降(P<0.05)。结论 本方法可以成功建立大鼠AMI模型并出现心功能的改变；大鼠体质量是在非人工通气条件下建立AMI模型的重要因素, 而胸廓的径线对模型成功率的影响还需进一步证实。
ABSTRACT: Objective To study the effects of weight and anteroposterior diameter-to-transverse diameter ratio on establishing a model of acute myocardial infarction (AMI) in rats without artificial ventilation and changes in left ventricular function after infarction. Methods Healthy SD rats were randomly divided into group A (200-250g), group B (250-300g), group C (>300g), and group D (control group). The left anterior descending (LAD) coronary artery was ligated to establish a model of myocardial infarction under spontaneous breathing condition immediately after thoracic lines were measured. And changes of electrocardiography were recorded after model establishment. At 2 and 4 weeks after AMI, we observed ventricular wall thickness and ventricular wall motion and measured the changes of cardiac function. Histomorphological changes and myocardial ultrastructure of the heart were observed under thoracotomy 2 weeks after operation. The above data were analyzed by SPSS13.0 statistics software. Results ① The first AMI rat model was established successfully after 30 times of experiments, and after 100 times the model？？s success rate gradually stabilized at about 83%. ② Group B and group C had a higher model success rate than group A (P<0.05), but group B and group C did not differ in modeling success rate (P>0.05). ③ There was no association between the rate of rat thoracic line and modeling success rate (P>0.05). ④ Two weeks after thoracotomy, ischemic myocardial color was white, and ventricular wall motion decreased. HE staining revealed that cardiomyocytes disappeared and were replaced by fibrous tissues and collagen. Remnant cardiomyocytes were arranged disorderly and myofibers were fractured, with interstitial damage and hyperplasia of fibrous tissue. Visible muscle cells were sparse and dissolved, the mitochondria had darker staining,