STRUCTURE AND PERMEABILITY OF GOBLET CELL TIGHT JUNCTIONS IN RAT SMALL-INTESTINE
STRUCTURE AND PERMEABILITY OF GOBLET CELL TIGHT JUNCTIONS IN RAT SMALL-INTESTINE
复制标题
DOI：
10.1007/bf01868490
复制
发表时间：
1982-01-01
影响因子：
2.4
通讯作者：
TRIER, JS
中科院分区：
文献类型：
--
作者：
MADARA, JL;TRIER, JS
两种主要的细胞类型，杯状细胞和吸收细胞，占主导地位的上皮衬里的小肠绒毛。大鼠回肠粘膜的冷冻断裂复制品被用来检查紧密连接结构的可能性，已知与跨上皮阻力有关，可能会随细胞类型而变化。吸收细胞之间的紧密连接结构均匀，而与绒毛杯状细胞相关的紧密连接显示出结构变异性。23%的绒毛杯状细胞紧密连接数< 4条，30%的绒毛杯状细胞紧密连接深度< 200 nm。相比之下，只有4%的吸收性细胞紧密连接具有< 4条链，并且只有9%的深度测量值< 200 nm。其他结构特征通常与绒毛杯状细胞紧密连接，但不太常见的吸收细胞紧密连接：缺乏链交联，自由末端的近腔链和高度片段化的链。在体内回肠段和外翻的环暴露于离子La。紧密连接和细胞旁间隙中密集的La沉淀物仅限于绒毛杯状细胞的亚群，而在绒毛吸收细胞之间没有发现。暴露后的预先固定的回肠袢镧1小时，微弱的沉淀物的La被发现在14%的紧密连接和细胞旁间隙的吸收细胞之间的紧密连接和细胞旁间隙的绒毛杯状细胞相比，42%。当在Ussing室中进行测试时，用于La暴露的方法没有降低跨上皮电阻。外翻环暴露于离子钡，并通过光学显微镜检查显示致密的钡沉淀物的交界区和区域的细胞旁间隙的绒毛杯状细胞，但不是在这些区域之间的吸收细胞。大分子示踪剂，微过氧化物酶，细胞色素c和辣根过氧化物酶，被排除在绒毛杯状细胞和吸收细胞旁空间在体内节段。绒毛杯状细胞的亚群可作为高离子渗透性的焦点部位，并有助于对离子流的相对低的阻力，这是小肠上皮的特征。
Two major cell types, goblet and absorptive cells, dominate the epithelial lining of small intestinal villi. Freeze-fracture replicas of rat ileal mucosa were used to examine the possibility that tight junction structure, known to relate to transepithelial resistance, might vary with cell type. Tight junctions between absorptive cells were uniform in structure while those associated with villus goblet cells displayed structural variability. In 23% of villus goblet cell tight junctions the strand count was < 4 and in 30% the depth was < 200 nm. In contrast, only 4% of absorptive cell tight junctions had < 4 strands and only 9% had depth measurements < 200 nm. Other structural features commonly associated with villus goblet cell tight junctions but less commonly with absorptive cell tight junctions were: deficient strand cross-linking, free-ending abluminal strands and highly fragmented strands. Both in vivo ileal segments and everted loops were exposed to ionic La. Dense La precipitates in tight junctions and paracellular spaces were restricted to a subpopulation of villus goblet cells and were not found between villus absorptive cells. After exposure of prefixed ileal loops to La for 1 h, faint precipitates of La were found in 14% of tight junctions and paracellular spaces between absorptive cells compared to 42% of tight junctions and paracellular spaces adjacent to villus goblet cells. When tested in Ussing chambers, the methods used for La exposure did not lower transepithelial resistance. Everted loops exposed to ionic Ba and examined by light microscopy showed dense Ba precipitates in the junctional zone and region of the paracellular space of villus goblet cells but not in these regions between absorptive cells. The macromolecular tracers, microperoxidase, cytochrome c and horseradish peroxidase, were excluded from both villus goblet cell and absorptive cell paracellular spaces in in vivo segments. A subpopulation of villus goblet cells may serve as focal sites of high ionic permeability and contribute to the relatively low resistance to ionic flow which characterizes the small intestinal epithelium.