Qin Huanlong, Zhang Zhongwei, Hang Xiaomin, Jiang Yanqun
Department of Surgery, Affiliated Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai 200233, PR China.
BMC Microbiol. 2009 Mar 31;9:63. doi: 10.1186/1471-2180-9-63.
It is increasingly recognized that Lactobacillus plantarum (L. plantarum) has the ability to protect against Enteropathogenic Escherichia coli (EPEC)-induced damage of the epithelial monolayer barrier function by preventing changes in host cell morphology, attaching/effacing (A/E) lesion formation, monolayer resistance, and macromolecular permeability. However, the cellular mechanism involved in this protective effect still remained to be clarified.
This study was to investigate the effect of L. plantarum on the changes of Caco-2 cells responding to Enteroinvasive Escherichia coli (EIEC), the permeability of cell monolayer and the transmissivity of dextran, and the distribution and expression of the tight junction (TJ) proteins, such as Claudin-1, Occludin, JAM-1 and ZO-1 were examined when infected with EIEC or adhesived of L. plantarum after infection by confocal laser scanning microscopy (CLSM), immunohistochemistry and Western blotting, the cytoskeleton protein F-actin were observed with FITC-phalloidin.
This study demonstrated that the transepithelial electrical resistance (TER) step down and dextran integrated intensity (DII) step up with time after infected with EIEC, but after treating with L. plantarum, the changes of TER and DII were improved as compared with EIEC group. L. plantarum prevented the damage of expression and rearrangement of Claudin-1, Occludin, JAM-1 and ZO-1 proteins induced by EIEC, and could ameliorate the injury of cytoskeleton protein F-actin infected with EIEC.
L. plantarum exerted a protective effect against the damage to integrity of Caco-2 monolayer cells and the structure and distribution of TJ proteins by EIEC infection.
人们越来越认识到，植物乳杆菌具有保护上皮单层屏障功能免受肠致病性大肠杆菌（EPEC）诱导损伤的能力，其作用机制包括防止宿主细胞形态改变、黏附/消除（A/E）损伤形成、单层电阻和大分子通透性改变。然而，这种保护作用所涉及的细胞机制仍有待阐明。
本研究旨在探讨植物乳杆菌对Caco-2细胞响应肠侵袭性大肠杆菌（EIEC）的变化、细胞单层通透性和葡聚糖透过率的影响，以及在感染EIEC或感染后黏附植物乳杆菌时，紧密连接（TJ）蛋白Claudin-1、Occludin、JAM-1和ZO-1的分布和表达情况，采用共聚焦激光扫描显微镜（CLSM）、免疫组织化学和蛋白质印迹法进行检测，并用FITC-鬼笔环肽观察细胞骨架蛋白F-肌动蛋白。
本研究表明，感染EIEC后，跨上皮电阻（TER）随时间下降，葡聚糖积分强度（DII）随时间升高，但用植物乳杆菌处理后，TER和DII的变化与EIEC组相比有所改善。植物乳杆菌可防止EIEC诱导的Claudin-1、Occludin、JAM-1和ZO-1蛋白表达和重排受损，并可改善EIEC感染引起的细胞骨架蛋白F-肌动蛋白损伤。
植物乳杆菌对EIEC感染所致Caco-2单层细胞完整性以及TJ蛋白结构和分布的损伤具有保护作用。
