两种微创Beagle犬心肌梗死模型的比较

摘要

目的：采用两种方法建立beagle犬心肌梗死动物模型并比较其效果。方法将30条Beagle犬随机分成三组，每组10条。①假手术组，开胸后剪开心包腔，不结扎冠状动脉。另外两组在电视胸腔镜辅助下用钛夹夹闭犬左冠状动脉前降支血管，②微创直视组，在胸骨左缘第3肋间开3�0 cm小切口，光源和操作器械均由此孔进入胸腔。③胸腔镜组，采用左侧第3肋间锁中线开孔1�0 cm，作为探测孔，电视胸腔镜由此进入胸腔，在第3肋间胸骨旁线及第4肋间锁中线处各开0�5 cm小孔作为操作孔，手术器械由此进入胸腔。造模后，测定心电图和血清肌酸激酶同工酶（ CK⁃MB）和肌钙蛋白I（ cTnI）含量变化，采用 HE染色了解各组的心肌病变情况。记录手术成功率、从皮肤切开开始到关胸所需要的时间和伤口愈合时间。结果与假手术组比较，两组动物出现明显的心肌梗塞改变（心电图st段抬高，血清CK⁃MB和cTnI水平增加，心肌缺血坏死纤维化，心肌细胞减少）。两种造模方法的犬存活率达90％，微创直视法所需时间明显较少，胸腔镜法切口愈合时间较短。结论微创手术建立的心肌梗塞模型，动物创伤小，死亡率低，是一种研究心肌梗塞病理生理机制的理想模型。%Objective The purpose of this study was to compare two types of myocardial infarction ( MI) models in Beagle dogs. Methods 30 dogs were divided randomly into three groups ( n =10 ) . ① The sham⁃operated group underwent pericardiotomy but without coronary artery ligation. The other two model groups were made under video⁃assisted thoracoscopy ( VATS) , where the left anterior descending coronary artery was closed by titanium clips:②The direct vision group:the minimally invasive closure of the artery was performed under direct vision. In this group, the thoracoscopic operation was performed through a 3�0 cm small incision opened at the margin of the left third rib. ③ The thoracoscopic group:the video⁃assisted thoracoscope was inserted into the chest through a 1�0 cm exploratory hole in the midline of the third rib, and the surgical instruments were inserted through two 0�5 cm operating holes at the para⁃sternum line of the third rib and midclavicular line of the fourth rib. Electrocardiogram ( ECG) was recorded and the levels of serum creatine kinase⁃MB ( CK⁃MB) and troponin I ( cTnI) were measured after modeling. The heart tissue samples were examined by histology using HE staining. The success rate of model establishment, durations from skin incision to chest closing and the wound healing were recorded. Results Compared with the sham⁃operated group, changes of myocardial infarction were observed in the two model groups ( ECG S⁃T segment elevation, increased serum CK⁃MB and cTnI levels, myocardial ischemia and fibrosis, and reduced amount of cardiomyocytes ) . The survival rate was 90% in both of the two model groups. The operating time was shorter in the minimally invasive surgery under direct vision group, and the wound healing time was shorter in the thoracoscopic group. Conclusions The myocardial infarction models generated by minimally invasive surgery have less trauma and low mortality in the dogs. This model is suitable for investigation of pathophysiological mechanism associated with myocardial infarction.