乳酸菌对感染肠上皮细胞通透性及紧密连接蛋白表达的影响

目的:研究乳酸菌对侵袭性大肠杆菌(EIEC) 感染肠上皮细胞(Caco-2)后,对其通透性和紧密连接(TJ)蛋白表达的影响. 方法:建立Caco-2 单层细胞感染模型.实验分为正常组、感染组、乳酸菌组和庆大霉素组.用电阻仪测定单层细胞的跨膜电阻值(TER),用高效液相法(HPLC)测定甘露醇透过率的变化,采用免疫组化法观察TJ相关蛋白,如Claudin-1蛋白,Occludin蛋白, JAM-1蛋白,ZO-1蛋白的分布和结构变化. 结果:EIEC感染Caco-2细胞后,单层细胞的TER值和甘露醇的透过率随时间延长而升高,而经乳酸菌处理后,TER值升高趋缓(P＜0.05),甘露醇的透过率降低(P＜0.05);EIEC感染后,相邻Caco-2细胞间TJ结构遭到破坏,TJ相关蛋白的表达亦减少,而乳酸菌处理后可使EIEC引起的TJ结构受损减轻、相关蛋白的表达增多. 结论:乳酸菌黏附于肠上皮细胞Caco-2后,可抑制EIEC破坏单层细胞的完整性,并改善TJ的结构变化和相关蛋白的表达分布.

Effect of Lactobacillus plantarun onlly regulating intestinal epithelial permeability and tight junction response to pathogenic bacteria

Abjective:To investigate the effect of Lactobacillus plantarun Onlly regulating the intestine epithelial permeability and tight junction proteins of enterocyte-like Caco-2 cells in responsing to Enteroinvasive Escherichia coli.Methods:In the model of Caco-2 monolayer cells,The cells were divided into four groups: normal group,infection group,Lactobacillus group and gentamicin group.The TER was measured by Milicell ERS and the transmissivity of mannitol was determined by HPLC.The distribution and structure of tight junction proteins,such as Claudin-1,Occludin,ZO-1,JAM-1 were examined by indirect IHC.Results: The TER and the transmissivity of mannitol increased after infected with EIEC,but the increase was decreased after dealing with Lactobacillus plantarun Onlly(P<0.05).The structure of tight junction was destroyed and the expression of tight junction proteins was diminished after infected with EIEC.But Lactobacillus plantarun Onlly can prevent the damage induced by EIEC.Conclusion:The Lactobacillus plantarun Onlly exerts a protective effect against the damage to integrity of Caco-2 monolayer cells and the structure and distribution of TJ proteins induced by EIEC infection.