自发性高血压大鼠心肌血管内皮生长因子表达水平的检测

Expression of vascular endothelial growth factor in myocardium of spontaneously hypertensive rats

目的探讨血管内皮生长因子(Vascularendothelialgrowthfactor,VEGF)在自发性高血压大鼠(Spontaneouslyhypertensiverat,SHR)心肌细胞中的表达情况,分析其与高血压时心肌毛细血管稀少及微小动脉“重塑”(remodeling)的关系。方法应用免疫组化SP染色法及计算机图像分析技术,对幼年(6周,n=15)和成年(12个月,n=15)SHR大鼠及幼年(6周,n=10)和成年(12个月,n=10)同系正常血压对照组京都Wistar大鼠(Wistar-Kyoto,WKY)心肌VEGF蛋白的表达水平进行了定量分析。结果在4组大鼠心脏各部(心房肌、心室肌、房间隔、室间隔等)心肌细胞浆中及冠状动脉各级分支的血管平滑肌细胞中均见有阳性VEGF表达,6周龄、12个月龄WKY及6周龄SHR三组间表达水平差异无统计学意义(P>0.05),而12个月龄SHR组表达水平较其他三组均高(P<0.05)。结论随着成年SHR大鼠血压的升高,心肌及血管平滑肌细胞中VEGF蛋白的表达水平上调,可能是对高血压所致的靶器官继发性毛细血管减少的一种代偿反应,高表达的VEGF可对抗由于缺氧诱导的内皮细胞凋亡,维持其存活,并促进微血管再生。

Objective To investigate the expression of vascular endothelial growth factor(VEGF)in myocardium of spontaneously hypertensive rats(SHR),and to analyze the relationship between the changed VEGF and the microvascular rarefaction,and arteriole remodeling.Method The immunohistochemistry-SP staining and computed image analysis system were used. The heart sections of 4 group of young (6 w old,n=15) and adult(12 m old,n=15) SHR rats,and young (6 w old,n=10) and adult (12 m old,n=10)Wistar-Kyoto rats were stained and quantitatively analyzed.Results The VEGF positive immunoreaction was found in the myocardial cells of the atria, ventricles, atrioventricular intersepta and in the smooth muscle cells of the coronary arteries of all hearts. The VEGF level was higher in 12 m old SHR group than in the other 3 groups(P<0.05).There were no statistically significant differences between the other 3 groups(P>0.05).Conclusions With the blood pressure rising, the expression of VEGF in the adult SHR hearts is upregulated. It is probably a compensatory reaction of the target organs to the microvascular rarefaction because of hypertension. The high expression of VEGF inhibits hypoxia-induced apoptosis of the endothelial cells,and enhances the capillary angiogenesis.