Dobrogowska D H, Lossinsky A S, Tarnawski M, Vorbrodt A W
New York State Office of Mental Retardation and Developmental Disabilities, Institute for Basic Research in Developmental Disabilities, Staten Island 10314, USA.
J Neurocytol. 1998 Mar;27(3):163-73. doi: 10.1023/a:1006907608230.
The early effects of intracerebrally infused vascular endothelial growth factor (VEGF) on the blood-brain barrier (BBB) to endogenous albumin were studied using a quantitative immunocytochemical procedure. In addition, transmission electron microscopy was used to observe morphological changes induced in brain vasculature. A solution of VEGF in saline (40 ng/10 microliters) was infused into the parieto-occipital cortex of mice, which were killed 10 min, 30 min, and 24 h afterwards. Untreated mice and mice that received infusion of saline only were used as controls. For immunocytochemical evaluation, ultrathin sections of immersion-fixed brain samples embedded in Lowicryl K4M were exposed to anti-albumin antiserum followed by protein A-gold. Simultaneously, other brain samples embedded in Spurr resin were used for ultrastructural examination. Morphometric and statistical analysis indicated that as soon as 10 min after infusion of VEGF, 33% of vascular profiles were leaking albumin, and this value increased at 30 min to 92%. This effect of VEGF appears to be of rather short duration because after 24 h, only 27% of vascular profiles showed signs of leakage. The results of ultrastructural observations indicate that VEGF (30 min post-infusion) induces several changes in microvascular segments located in the area of intracerebral infusion of VEGF. These changes consist of the appearance of interendothelial gaps; fragmentation of the endothelium with formation of segmental, fenestrae-like narrowings; degenerative changes of the vascular basement membrane; and the appearance of fibrin gel in the vessel lumen. At 24 h post-infusion, solitary diaphragmed fenestrae appeared in attenuated segments of the endothelium in a few microvascular profiles. These changes, which are interpreted to be preparatory steps for angiogenesis, affect the structural integrity of the vascular segments, leading to extravasation of blood plasma proteins, including albumin.
采用定量免疫细胞化学方法研究了脑内注入血管内皮生长因子（VEGF）对血脑屏障（BBB）内源性白蛋白的早期影响。此外，利用透射电子显微镜观察脑脉管系统诱导的形态学变化。将VEGF生理盐水溶液（40 ng/10微升）注入小鼠顶枕叶皮质，分别于10分钟、30分钟和24小时后处死小鼠。未处理的小鼠和仅接受生理盐水注入的小鼠作为对照。为进行免疫细胞化学评估，将包埋于Lowicryl K4M中的浸没固定脑样本超薄切片暴露于抗白蛋白抗血清，随后用蛋白A金处理。同时，将包埋于Spurr树脂中的其他脑样本用于超微结构检查。形态计量学和统计学分析表明，注入VEGF后10分钟，33%的血管轮廓有白蛋白渗漏，30分钟时该值增至92%。VEGF的这种作用似乎持续时间较短，因为24小时后，只有27%的血管轮廓有渗漏迹象。超微结构观察结果表明，VEGF（注入后30分钟）在VEGF脑内注入区域的微血管段诱导了几种变化。这些变化包括内皮间隙的出现；内皮细胞碎片化，形成节段性、窗孔样狭窄；血管基底膜的退行性变化；以及血管腔内纤维蛋白凝胶的出现。注入后24小时，少数微血管轮廓中内皮细胞减薄段出现单个有隔膜的窗孔。这些变化被认为是血管生成的准备步骤，影响血管段的结构完整性，导致血浆蛋白包括白蛋白外渗。
