SHR大鼠血压升高前后脑内VEGF的变化及其意义

THE VARIATION AND ITS SIGNIFICANCE OF THE VEGF EXPRESSION IN THE BRAINS OF SHRs

为探讨自发性高血压大鼠(SHR)血压升高前后脑内血管内皮生长因子(VEGF)表达水平的变化及其意义,本研究应用免疫组化SP法及计算机图像分析技术,对幼年(6周龄)和成年(12月龄)SHR大鼠及幼年(6周龄)和成年(12个月龄)同品系正常血压对照组京都Wistar大鼠(WKY)脑切片VEGF蛋白的表达水平进行了定量分析。结果发现在4组大鼠大脑皮质的广泛区域、纹状体、室管膜上皮及脉络丛等处均观察到散在分布的VEGF样免疫阳性细胞,阳性反应产物呈棕色颗粒状,位于胞浆中,其中幼年和成年WKY及幼年SHR三组间阳性细胞数及其灰度差异无显著性(P>0.05),而12月龄SHR组阳性细胞数及其灰度均高于其它三组(P<0.05)。以上结果提示:随着成年SHR大鼠血压的升高,脑内VEGF蛋白的表达水平上调,高表达的VEGF可能对高血压时脑缺血缺氧诱导的血管内皮细胞凋亡及微血管的存活有保护意义,同时也可能参与了高血压所致的脑损伤。

To investigate the expression level of vascular endothelial growth factor（VEGF） in the brains of spontaneously hypertensive rats （SHRs） , before and after the blood pressure rose, the immunohistochemistry-SP method combined with image analysis were used. The sections of four group＇s hrains of the young SHR （6 w old, n=15 ）, adult SHR（ 12 m old, n=15 ） and the young Wistar-Kyoto rat （WKY） （6 w old, n = 10） ,adult WKY（ 12 m old, n = 10） were stained and quantitatively analyzed. The VEGF-Iike immunoreactive （ LI ） products were observed in the cerebral cortex, striatum, chorold plexus and endothelium of ependyma. The numbers and their gray degree of VEGF-LI cell bodies were higher in 12 m SHR group than that in the other 3 groups （ P 〈0.05 ）. However, the differences among the other 3 groups had no statistical significance （ P 〉0.05 ）. The above results demonstrated that with the blood pressure rising, the expression of VEGF in the adult SHR brains was up-regulated. The high expressing of VEGF might have protective significance to hypoxia-inducible apoptosis of the endothelial cells, and retain the capillary survival. Meanwhile, the increased VEGF might play a role in the lesion of the brain by hypertension.