益生菌与肠黏膜互作的分子机制研究进展

益生菌是一类定植于动物肠道，可辅助动物消化功能，维护肠道菌群平衡并可影响肠道免疫系统，有益于动物健康的重要调节性菌群。该类菌群与动物肠上皮细胞间互作的分子机制包括菌体表面分子如磷脂壁酸（phosphatidicacid，LTA）、表面层蛋白（Slayerprotein）等与宿主的粘附相关蛋白分子结合，通过占位效应抑制有害菌群在肠道内的定植；益生菌还可刺激肠道细胞分泌B防御素2、细菌素和有机酸等可抑制甚至杀灭有害菌群；在益生菌作用下，肠道上皮细胞可增强粘液糖蛋白、紧密连接蛋白occludin和ZO-1等分子的表达，加厚并加固肠道黏膜屏障；益生菌相关抗原可通过与抗原递呈细胞表面模式识别受体（TLRs等）分子结合，激活递呈细胞，启动各免疫细胞的交互作用，调节肠道免疫状态。

Molecular mechanisms of interaction between probiotics and intestinal mucosa

Probiotics are described as microorganisms that aid host in digestion, improve gut microbiota balance and help modulation of the host immune system. One of the molecular mechanisms of interaction between probioties and intestinal epithelial cells is the binding of probiotic components such as phosphatidie acid （LTA） and S layer protein to adhesion molecules of the host, which will inhibit the adhesion of pathogens. Probiotics could stimulate the induction of antimierobial substances, such as 13-defensin 2, baeteriocins and organic acids, which could kill or inhibit the growth of pathogens. Probiotics could also reinforce the intestinal mucosal barrier by increase the se- cretion of mucus glyeoprotein and tight junction proteins （ Claudin and ZO-1 ） by host cells. The recognition of pro- biotic components （pathogen associated molecular patterns, PAMPs ） by host TLRs will activate the dendritic cells, initiate interactions between imnmne cells and affect the intestinal immune regulation.