慢性心力衰竭大鼠心肌毛细血管密度及血管内皮生长因子变化

目的观察慢性心力衰竭大鼠心肌毛细血管密度及血管内皮生长因子(VEGF)变化,探究冠脉微循环障碍的病理特点及病因机制.方法实验组(n=15)皮下注射异丙肾上腺素,对照组(n=10)皮下注射生理盐水,间隔24h,连续2次.12周后测定血液动力学;计算左心室重量/体重;HE染色、Masson染色分别观察左心室病理改变、胶原变化;西非单叶豆素组织化学染色结合图像分析确定心内膜下心肌毛细血管密度、心肌细胞密度、毛细血管密度与心肌细胞密度的比值(毛细血管/心肌细胞);观察心内膜下心肌VEGF免疫组织化学变化.结果同对照组比较,实验组左心室收缩、舒张功能下降(P<0.05);左心室重量/体重升高(P<0.001);心内膜下心肌散在坏死,胶原沉积;心内膜下心肌毛细血管密度、心肌细胞密度、毛细血管/心肌细胞下降(P<0.05);VEGF合成增加(P<0.001).结论慢性心力衰竭大鼠心内膜下心肌毛细血管分布稀疏;该区域毛细血管代偿性生成减少与心肌VEGF表达无关.

CHANGES OF MYOCARDIAL CAPILLARY DENSITY AND VASCULAR ENDOTHELIAL GROWTH FACTOR IN RATS WITH CHRONIC HEART FAILURE

Objective To explore the pathology and etiology of coronary microcirculation dysfunctionthrough the changes of myocardial capillary density and vascular endothelial growth factor (VEGF)in rats with chronic heart failure. Methods The experimental group, composed of 15 rats, was subcutaneously given with isoproterenol subcutaneously twice every 24 hours, while the control group, composed of 10 rats, was given saline in the same way. After 12 weeks, hemodynamic measurement and the ratio of left ventricular weight to body weight were obtained. Haematoxylin and eosin staining and Masson staining were used to observe the changes of left ventricular myocardial pathology and collagen, respectively. Griffonia simplicifolia I-B_ 4histochemical staining together with image analysis was applied to determine the capillary density, the myocardial cell density and the ratio of capillary density to myocardial cell density (C/M) in the subendocardial myocardium. The change in VEGF was observed by immunohistochemical staining in this region. Results Compared with that of the control group, the left ventricular systolic and diastolic function was decreased in the experimental group (P<0.05), while the ratio of left ventricular weight to body weight was increased (P<0.001). In the subendocardial myocardium, disperse necrosis and collagen deposition appeared in the experimental group, with decreased capillary density, myocardial cell density and C/M (P<0.05), and upregulated VEGF (P<0.001), as compared with those in the control group. Conclusion Capillary rarefaction appeared in the subendocardial myocardium in rats with chronic heart failure, and the reduction in angiogenesis was not correlated with the expression of myocardial VEGF.