Otte Jan-Michel, Kiehne Karlheinz, Herzig Karl-Heinz
First Department of Medicine, St. Josef-Hospital, University of Bochum, Bochum, Germany.
J Gastroenterol. 2003;38(8):717-26. doi: 10.1007/s00535-003-1136-5.
The intestinal mucosa has to withstand exposure to a variety of substances, challenges in pH, temperature, and osmolarity; and, finally, bacterial products which might induce local and systemic inflammatory responses. The mucosal integrity is conserved by a defense system which consisting of constitutive and inducible mechanisms. These include the physical barrier function; the secretion of factors into the lumen, such as mucins and antibacterial substances; the mucosal immune system; and, finally, the ability of the mucosa to reconstitute once damage has occurred. The homeostasis and integrity of the gastrointestinal mucosa ultimately depends upon the balance between defensive and aggressive factors. While the physical barrier function was formerly believed to play the major role in mucosal protection against luminal bacteria, the recent discovery of Toll-like receptors and antimicrobial peptides in the intestinal epithelium has modified the concept of intestinal defense towards a more active character, which will be discussed in this review.
肠道黏膜必须承受各种物质的暴露、pH值、温度和渗透压的挑战；最后，还要承受可能引发局部和全身炎症反应的细菌产物。黏膜的完整性由一个防御系统维持，该系统由组成性和诱导性机制组成。这些机制包括物理屏障功能；向肠腔内分泌诸如黏蛋白和抗菌物质等因子；黏膜免疫系统；最后，黏膜在受损后进行自我修复的能力。胃肠道黏膜的稳态和完整性最终取决于防御因素和侵袭因素之间的平衡。虽然以前认为物理屏障功能在黏膜抵御肠腔内细菌方面起主要作用，但最近在肠道上皮细胞中发现的Toll样受体和抗菌肽改变了肠道防御的概念，使其具有更积极的特性，本文将对此进行讨论。
