Mills A N, Haworth S G
Department of Paediatric Cardiology, Institute of Child Health, London, England.
J Thorac Cardiovasc Surg. 1991 May;101(5):909-16.
Capillary permeability is partly determined by the distribution of anionic charge on the endothelial cell membrane and organelles and on the biochemical composition of these structures. Therefore the pulmonary capillaries of 18 Large White pigs aged less than 10 minutes, 1 week, and 6 months (six animals at each age) were perfused with cationized ferritin and the peroxidase conjugated lectins Dolichos bifloris, concanavalin A, Triticum vulgaris, and Ricinus communis type 2. Lectins bind to the carbohydrate cell surface antigen for which each shows monosaccharide specificity. The ultrastructural localization of each substance on the capillary endothelial cell was studied, and the length of labeled cell membrane was measured. The proportion of intracellular vesicles containing cationized ferritin was also determined. Binding of cationized ferritin to cell membrane and the number of cationized ferritin-labeled vesicles decreased between birth and 1 week (p less than 0.01 for both). Binding of lectins Triticum vulgaris and Dolichos bifloris decreased between birth and 1 week (p less than 0.01 for both) and between 1 week and adulthood (p less than 0.01 for Dolichos bifloris). Binding of concanavalin A and Ricinus communis type 2 showed a nonsignificant increase with age. Thus the area of pulmonary endothelial cell membrane and the proportion of vesicles with a negative charge decreased after birth, and the distribution of cell surface glycoconjugates also changed. Because these microdomains form differentiated pathways that help control transcellular movement of water and solutes, the findings help explain the greater permeability of the newborn lung.
毛细血管通透性部分取决于阴离子电荷在内皮细胞膜和细胞器上的分布以及这些结构的生化组成。因此，用阳离子铁蛋白和过氧化物酶结合凝集素双花扁豆、伴刀豆球蛋白A、普通小麦和蓖麻凝集素2对18只年龄小于10分钟、1周和6个月的大白猪（每个年龄段6只动物）的肺毛细血管进行灌注。凝集素与碳水化合物细胞表面抗原结合，每种凝集素都显示出单糖特异性。研究了每种物质在毛细血管内皮细胞上的超微结构定位，并测量了标记细胞膜的长度。还测定了含有阳离子铁蛋白的细胞内囊泡的比例。出生至1周期间，阳离子铁蛋白与细胞膜的结合以及阳离子铁蛋白标记囊泡的数量减少（两者均p<0.01）。出生至1周期间以及1周与成年期之间，普通小麦凝集素和双花扁豆凝集素的结合减少（两者均p<0.01）。伴刀豆球蛋白A和蓖麻凝集素2的结合随年龄增长无显著增加。因此，出生后肺内皮细胞膜面积和带负电荷囊泡的比例降低，细胞表面糖缀合物的分布也发生了变化。由于这些微区形成了有助于控制水和溶质跨细胞转运的不同途径，这些发现有助于解释新生儿肺通透性较高的原因。
