Lane N J, Revest P A, Whytock S, Abbott N J
Physiology Department, Queen Mary & Westfield College, London, UK.
J Neurocytol. 1995 May;24(5):347-60. doi: 10.1007/BF01189062.
A comparison was made between endothelial cells in freshly-isolated rat brain microvessels, and following culture of the cells for 1-10 days during growth to confluence. Attention focused on tight junctions and vesicular structures, as seen in thin sections and freeze-fracture replicas. Freshly-isolated vessels had an abnormal appearance, with a profusion of luminal microvillar processes, and extensive cytoplasmic vacuolation. There were numerous vesicular profiles, reaching a density of approximately 60 microns-2, and with a large proportion open to the surface, as shown by labelling with cationized ferritin at 4 degrees C for 5 min. Junctional zones were relatively loosely organized, with evidence for some cell:cell separation, as well as some residual tight junctional sites within zonula adhaerens junctions. In freeze-fracture replicas, junctional strands showed segments of tightly packed intramembrane particles, generally on the P face. After 1 day in culture, the cells appeared more normal, with no vacuolation or luminal processes. Vesicles were still numerous, some associated with junctional zones, while tight junctions were relatively sparse; freeze-fracture showed some incomplete tight junctional strands, with some of the intramembrane particles fracturing onto the E face. The double offset fibrillar nature of the strands could occasionally be seen. Cells cultured for 4 and 10 days showed a progressive increase in the completeness of the junctional zone, with more tight junctional contacts within the length of the adhaerens junction, and an aggregation of microfilaments in the underlying cytoplasm. The number of vesicular profiles declined, and they were progressively excluded from the junctional zone. These observations have relevance for studies on the physiology of the brain endothelium in vitro, and for comparisons with the in vivo condition.
对新鲜分离的大鼠脑微血管内皮细胞以及细胞在生长至汇合状态的过程中培养1 - 10天之后的内皮细胞进行了比较。研究重点关注紧密连接和囊泡结构，这些结构在超薄切片和冷冻蚀刻复制品中可见。新鲜分离新鲜分离的血管外观异常，有大量腔内微绒毛突起以及广泛的细胞质空泡化。有许多囊泡轮廓，密度约为60个/微米²，并且如在4℃用阳离子化铁蛋白标记5分钟所示，很大一部分囊泡向表面开放。连接区组织相对松散，有一些细胞间分离的迹象，以及黏着连接带内一些残留的紧密连接位点。在冷冻蚀刻复制品中，连接索显示出紧密堆积的膜内颗粒段，通常在P面。培养1天后，细胞看起来更正常，没有空泡化或腔内突起。囊泡仍然很多，一些与连接区相关，而紧密连接相对稀疏；冷冻蚀刻显示一些不完整的紧密连接索，一些膜内颗粒断裂到E面。索的双偏移纤维性质偶尔可见。培养4天和10天的细胞显示连接区的完整性逐渐增加，在黏着连接长度内有更多紧密连接接触，并且在其下方的细胞质中有微丝聚集。囊泡轮廓的数量减少，并且它们逐渐被排除在连接区之外。这些观察结果与体外脑内皮生理学研究以及与体内情况的比较相关。
