Wang B, Chen J, Wang S, Zhao X, Lu G, Tang X
1 Jiangsu Academy of Science and Technology for Inspection and Quarantine, Nanjing, Jiangsu, 210001, China P.R.
2 Department of Travel Health, Nanjing Entry-Exit Inspection and Quarantine Bureau, Nanjing, Jiangsu, 211106, China P.R.
Benef Microbes. 2017 May 30;8(3):497-505. doi: 10.3920/BM2016.0019. Epub 2017 Apr 26.
Translocation of bacteria across the intestinal barrier is important in the pathogenesis of systemic sepsis and multiple organ dysfunction syndromes. Inflammatory cytokines increase paracellular permeability that allows increased luminal bacteria to translocate across mucosal epithelium and further deteriorate the gut barrier. In order to reduce this risk, the prophylactic use of probiotics has been recently addressed. In this paper, we investigate the protective role toward tumour necrosis factor (TNF)-α induced non-pathogenic Escherichia coli translocation across Caco-2 monolayers of Lactobacillus strains. According to our experimental data, Lactobacillus plantarum L9 and Lactobacillus acidophilus LA have good capacities to adhere to Caco-2 cells. Addition of L. plantarum L9 and L. acidophilus LA to the enterocyte monolayer surface result in significant inhibition of E. coli adhesion and cell internalisation. However, L. plantarum L9 and L. acidophilus LA did not inhibit the growth of the non-pathogenic E. coli B5 after 24 h incubation. Exposure to TNF-α for 6 h caused a dramatic increase in E. coli B5 translocation across Caco-2 cells, which was uncoupled from increases in paracellular permeability. Pretreatment with L. plantarum L9 prevent TNF-α induced transcellular bacterial translocation and IL-8 production in Caco-2 cells. L. plantarum L9 also did not affect the integrity of the monolayers, as indicated by lactate dehydrogenase release, horseradish peroxidase permeability, and transepithelial electrical resistance. L. plantarum L9 showed the potential to protect enterocytes from an acute inflammatory response and therefore could be good potential prophylactic agents in counteracting bacterial translocation.
细菌穿过肠道屏障的易位在全身性脓毒症和多器官功能障碍综合征的发病机制中具有重要意义。炎性细胞因子会增加细胞旁通透性，使更多的管腔细菌穿过黏膜上皮易位，进而使肠道屏障进一步受损。为降低这种风险，近期人们开始关注益生菌的预防性使用。在本文中，我们研究了乳酸杆菌菌株对肿瘤坏死因子（TNF）-α诱导的非致病性大肠杆菌穿过Caco-2单层细胞易位的保护作用。根据我们的实验数据，植物乳杆菌L9和嗜酸乳杆菌LA具有良好的黏附Caco-2细胞的能力。将植物乳杆菌L9和嗜酸乳杆菌LA添加到肠上皮细胞单层表面可显著抑制大肠杆菌的黏附和细胞内化。然而，在孵育24小时后，植物乳杆菌L9和嗜酸乳杆菌LA并未抑制非致病性大肠杆菌B5的生长。暴露于TNF-α 6小时会导致大肠杆菌B5穿过Caco-2细胞的易位显著增加，这与细胞旁通透性的增加无关。用植物乳杆菌L9预处理可防止TNF-α诱导的Caco-2细胞跨细胞细菌易位和IL-8产生。植物乳杆菌L9也不影响单层细胞的完整性，这通过乳酸脱氢酶释放、辣根过氧化物酶通透性和跨上皮电阻得以体现。植物乳杆菌L9显示出保护肠上皮细胞免受急性炎症反应影响的潜力，因此可能是对抗细菌易位的良好潜在预防剂。
