Vorbrodt A W, Dobrogowska D H
New York State Office of Mental Retardation and Developmental Disabilities, Institute for Basic Research in Developmental Disabilities, Staten Island.
Folia Histochem Cytobiol. 1994;32(2):63-70.
The blood-brain barrier (BBB) to endogenous albumin was studied in normal adult, newborn and aged mice by using quantitative immunocytochemical procedures. For control purposes, the non-BBB-type of microvasculature from skeletal muscle (diaphragm) was also examined. Thin sections of tissue samples embedded at low temperature in hydrophilic resin Lowicryl K4M were exposed to anti-mouse albumin antiserum followed by protein A-gold. Labelling density was recorded over four compartments: vascular lumen, endothelium, subendothelial (perivascular) space and adjacent neuropil. The labeling density of the vessel lumen was considered to represent 100% of circulating albumin. The main differences between the two types of microvasculature consisted in the appearance of one-fifth of the labeling density of circulating albumin in the perivascular space of the non-BBB-type and only about one one-hundredth in the perivascular space of the BBB-type microvessels. The results suggest that the barrier function of brain microvasculature to endogenous albumin in newborn and aged mice is not significantly different from that in normal, adult animals. However, applied morphometrical and quantitative analysis of the density of immunolabeling over the above-mentioned compartments makes it possible to detect even subtle deviations from normal values in both extreme-age groups.
采用定量免疫细胞化学方法，研究了正常成年、新生和老年小鼠血脑屏障（BBB）对内源性白蛋白的作用。作为对照，还检测了骨骼肌（膈肌）非血脑屏障型微血管。将低温包埋于亲水性树脂Lowicryl K4M中的组织样本制成薄片，先用抗小鼠白蛋白抗血清处理，再用蛋白A-金处理。记录四个区域的标记密度：血管腔、内皮、内皮下（血管周）间隙和相邻神经纤维网。血管腔的标记密度被视为代表循环白蛋白的100%。两种类型微血管的主要区别在于，非血脑屏障型微血管的血管周间隙中循环白蛋白的标记密度为五分之一，而血脑屏障型微血管的血管周间隙中仅约为百分之一。结果表明，新生和老年小鼠脑微血管对内源性白蛋白的屏障功能与正常成年动物无显著差异。然而，通过对上述区域免疫标记密度进行形态计量学和定量分析，即使在两个极端年龄组中，也能够检测到与正常值的细微偏差。
