兔心肌梗死左心室重构过程的 MRI 表现与病理对照研究

摘要

Objective To study the pathologic basis and the value of CMRI for left ventricular remodeling during AMI.Methods To make the rabbits model of myocardial infarction by ligation of the left anterior descending (LAD) coronary artery and left circumflex (LCX) coronary artery.CMRI was performed at different stage of myocardial infarction ,in the meantime the normal control group and ischemic experiment group of different time were stained with TTC and HE .Results Between infarction areas and the corresponding non infarct zone , there was statistically significant difference in the ESd of 30 minutes ischemia ,and also in the EDd and of the other groups ( P<0 .05 ) , and there was statistically significant difference of EDd and Esd in infarct area between the different time of ischemia group ( P<0 .05 ) ,the results showed that the activity of infarct zone was reduced with the corresponding non infarcted areation in left ventricular wall , EDd and ESd of the left ventricles were gradual decrease along with the longer time of infarction , the walls were obvious thin after two weeks , but less changing;There was statistically significant difference of ESV and EF in control and experiment groups of different time ,from 30 min to 8 h or from 1 d to 4 weeks, there was statistically significant difference of ESV and EF between the different time of ischemia groups within that range (P<0.05),between 1 d and 4 weeks in group,the difference of ESV and EF had no statistical significance ( P >0 .05 ) , the results showed that EDV and ESV were gradual increase,and EF decrease ,it′s more obviously one day later ,but steadying after one week; The imaging of CMRI were consistent with TTC;The trauma of lesion was more and more serious with HE .In the early stage ,myocardial cells showed wavilness , the fibers were broken , necrotic myocardium stained more obviously with HE after three days,the area of around lesion began to fibrose ,and fibrous scars formed at four weeks .Conclusions The causes of thinning of the left ventricle walls were myocardial trauma and fibrous scars recovery ,it′s important clinic value for CMRI to evaluate left ventricular remodeling during AMI in vitro.%目的探讨急性心肌梗死（AMI）过程中左心室重构心脏MRI（CMRI）变化的病理基础及CM-RI对左心室重构的应用价值。方法结扎冠状动脉左前降支（ LAD ）及左旋支（ LCX ），制备兔心肌梗死模型，选取不同时相行CMRI 检查，同时对正常及不同缺血时间组梗死心肌标本进行 TTC、HE 染色观察。结果缺血30 min组收缩末期室壁厚度（ ESd ）及其余各缺血时间组的梗死区与相应非梗死区之间舒张末期室壁厚度（EDd）和ESd差异有统计学意义（P＜0．05），各缺血时间组梗死区之间的EDd和ESd差异有统计学意义（P＜0．05），提示左心室壁梗死区活动较相应非梗死区降低，且随着缺血时间延长，EDd和ESd逐渐降低，至2～4周室壁厚度明显变薄但变化较小；各缺血时间组与正常对照组ESV、EF均P＜0．05，各缺血时间组ESV均增大，而EF则降低，各缺血时间组间比较显示30 min至8 h各组与1 d至4周各组之间ESV、EF均P＜0．05，3 d至4周各组与1 d组均P＜0．05，1周与4周组之间ESV、EF差异无统计学意义（ P＞0.05），提示EDV及ESV逐渐增大， EF逐渐降低，1 d后进一步加重，1～4周基本稳定；CMRI表现与大体TTC染色一致；HE染色显示随着缺血时间延长，心肌损伤逐渐加重，缺血早期心肌细胞呈波浪状改变，肌纤维断裂，缺血3d后梗死区坏死心肌细胞伊红染色明显加深，缺血2周梗死区周边开始纤维化，4周后梗死区形成纤维瘢痕。结论 AMI后左心室重构主要由于心肌损伤、瘢痕修复引起，CMRI体外评价AMI后左心室重构具有重要临床应用价值。