论文部分内容阅读
探讨大鼠急性心肌梗死(AMI)后不同时间点心脏血流动力学参数、心肌组织病理学和c-kitmRNA表达水下的变化及三者之间的相互关系。66只成年雄性SD大鼠随机分为:正常组、假手术组和结扎组。通过结扎冠状动脉左前降支建立AMI模型。实验结束后,检测心脏血流动力学参数、心肌组织病理学变化和c-kit mRNA的表达水平。结果表明,正常组与各假手术组间血流动力学参数无明显差异(P>0.05)。与正常组相比,各结扎组的左心室收缩压(LVSP)、左心室内压力最大上升速率和最大下降速率(±dp/dtmax)均明显降低(P<0.01);左心室舒张末期压力(LVEDP)明显上升(P<0.01)。但与结扎6 h组相比,其余各结扎组的LVSP、LVEDP、±dp/dtmax均明显升高(P<0.05)。结扎区心肌组织HE染色显示,与正常组相比,6 h结扎组心肌细胞无明显形态学改变;1 d结扎组细胞核固缩或碎裂,横纹不清或消失,大量心肌发生坏死;3 d结扎组心肌细胞结构消失,坏死区形成,并可见大量炎症细胞浸润;7 d结扎组中性多核细胞浸润更加明显,弥漫整个坏死区域;14 d结扎组可见梗死区周边有肉芽组织长入,并伴大量的中性多核细胞浸润。RT-PCR显示,c-kit mRNA在正常组和假手术组心肌组织中有低水下表达,但二者无明显差异(P>0.05)。结扎各组从3 d到14 d,心肌组织中c-kit mRNA表达分别为相应假手术组的1.46倍、1.91倍、2.67倍。提示,AMI后前2周内,受损心肌组织结构和心脏功能已开始修复,而c-kit+心肌干细胞在心肌的再生修复过程中可能发挥重要作用。
To investigate the changes of cardiac hemodynamics, myocardial histopathology and c-kit mRNA expression at different time points after acute myocardial infarction (AMI) in rats and their correlations. Sixty-six adult male Sprague-Dawley rats were randomly divided into normal group, sham operation group and ligation group. The AMI model was established by ligation of the left anterior descending coronary artery. At the end of the experiment, cardiac hemodynamic parameters, myocardial histopathological changes and c-kit mRNA expression were measured. The results showed that there was no significant difference in hemodynamic parameters between normal group and sham operation group (P> 0.05). Compared with the normal group, the left ventricular systolic pressure (LVSP), the maximum rate of left ventricular pressure and the maximum rate of decrease (± dp / dtmax) in each group were significantly decreased (P <0.01); left ventricular end-diastolic pressure LVEDP) increased significantly (P <0.01). However, the LVSP, LVEDP and ± dp / dtmax of the other ligation groups were significantly higher than those of the 6 h group (P <0.05). HE staining of myocardial tissue in the ligation zone showed that compared with the normal group, there was no obvious morphological changes of the myocardial cells in the 6 h ligation group. In the ligation group, the nuclei were pyknotic or fragmented, In the ligation group, the structure of cardiomyocytes disappeared and the necrotic area was formed, and a large number of infiltrating inflammatory cells could be seen. The infiltration of neutral multinucleated cells in the ligation group was more obvious on the 7th day, which filled the entire necrotic area. Accompanied by a large number of neutrophilic infiltration. RT-PCR showed that c-kit mRNA was expressed at low level in myocardium of normal group and sham operation group, but there was no significant difference between the two groups (P> 0.05). From 3 days to 14 days after the ligation, the c-kit mRNA expression in myocardial tissue was 1.46 times, 1.91 times and 2.67 times respectively in the corresponding sham operation group. It is suggested that myocardial tissue structure and cardiac function of damaged myocardium have begun to be repaired in the first 2 weeks after AMI, and c-kit + cardiac stem cells may play an important role in myocardial regeneration and repair.