Studies on the colonization mechanism of indigenous bacteria in alimentary tract

本研究阐明了土著细菌在大鼠消化道的定植机制。本研究获得的结果如下：1.原生菌的基本定植部位是肠绒毛和Peyer‘s小结中凋亡晚期的上皮细胞。滤泡相关上皮(FAE)中M细胞的分化与本地细菌在FAE及其邻近粘膜上的定植有关。普通柱状上皮细胞吞噬了退化的细菌，而M细胞吞噬了Peyer‘s斑块FAE中的完整细菌。细菌的这种吞噬作用可能与M细胞的膜受体有关。组织化学显示晚期凋亡的上皮细胞有特异糖的表达，而M细胞无特异糖的表达。原生菌的基本定植部位是整个消化道中凋亡晚期的上皮细胞。本土细菌从这些部位向粘膜深处扩散。这种增殖是由邻近的粘膜淋巴滤泡的FAE监测的。在细菌附着部位，原生细菌被上皮细胞骨架重排的物理防御和抗菌物质分泌的化学防御所消除。在透射电子显微镜下观察到Peyer‘s斑块的FAE中有详细的分化和再分化过程。

This research clarified the colonization mechanisms of indigenous bacteria in rat alimentary tracts. The results obtained in this research are as follows:1. Fundamental colonization site of indigenous bacteria is the epithelial cells with late apoptotic stage in intestinal villi and Peyer's patches.2. Differentiation of M cells in the follicle-associated epithelium (FAE) is co-related with the colonization of indigenous bacteria on FAE and neighboring mucosa. The ordinary columnar epithelial cells engulf the degenerated bacteria, whereas M cells engulf the intact bacteria in FAE of Peyer's patches. This engulfment of bacteria might be mediated with membrane receptor in M cells form ultrastructural findings.3. Specific sugar expression was histochemically determined on the epithelial cells with late apoptotic stage, whereas M cells expressed no specific sugar.4. Fundamental colonization site of indigenous bacteria is the epithelial cells with late apoptotic stage in entire alimentary tract. From these sites, indigenous bacteria proliferate deeply into mucous membrane. This proliferation is monitored by neighboring FAE of mucous lymphatic follicles.5. At bacterial attachment sites, indigenous bacteria are eliminated by both the physical defense of rearrangement of epithelial cytoskeletons and the chemical defense of secretion of antibactericidal substances.6. The detailed differentiation and re differentiation processes were clarified in FAE of Peyer's patches under transmission electron microscope.