Biological and Soil Faculty of St. Petersburg University, St. Petersburg, Russia.
J Comp Physiol B. 2010 Apr;180(4):591-8. doi: 10.1007/s00360-009-0440-7. Epub 2010 Jan 5.
In tubular epithelia, barrier function varies in a segment-specific way. The aim of this study was to correlate the presence of tight junction proteins and paracellular barrier properties along rat intestine. Tissue segments of duodenum, jejunum, ileum, and colon were stripped of submucosal cell layers and mounted in Ussing chambers for impedance spectroscopy to measure epithelial resistance (R (epi)). In parallel, expression of tight junction proteins was analysed by Western blots and immune fluorescence confocal microscopy. Colon showed highest R (epi), followed by duodenum, jejunum, and ileum. In small intestine, common transepithelial resistance (R (trans) or TER) overestimated true R (epi) by approximately 60%. In colon, strongest expression of "tightening" claudins 1, 3, 4, 5, and 8 was detected. In accordance with R (epi) the most proximal of the small intestinal segments, duodenum exhibited highest expression of "tightening" claudins and lowest expression of claudins mediating permeability, namely claudin-2, -7, and -12, compared to jejunum and ileum. These results correspond to the specific role of the duodenum as the first segment facing the acidic gastric content.
在管状上皮中，屏障功能以节段特异性的方式变化。本研究旨在探讨大鼠肠道中紧密连接蛋白的存在与细胞旁屏障特性之间的相关性。将十二指肠、空肠、回肠和结肠的组织段从黏膜下层细胞层中剥离出来，然后安装在 Ussing 室中进行阻抗谱测量上皮电阻 (R(epi))。同时，通过 Western blot 和免疫荧光共聚焦显微镜分析紧密连接蛋白的表达。结果显示，结肠的 R(epi)最高，其次是十二指肠、空肠和回肠。在小肠中，常见的跨上皮电阻 (R(trans)或 TER) 高估了真实的 R(epi)约 60%。在结肠中，检测到“收紧”claudin 1、3、4、5 和 8 的表达最强。与 R(epi)一致，小肠的近端段十二指肠与空肠和回肠相比，“收紧”claudin 的表达最高，而通透性调节 claudin-2、-7 和 -12 的表达最低。这些结果与十二指肠作为第一个面对酸性胃内容物的节段的特殊作用相对应。
