Probiotics are efficacious in the treatment of inflammatory bowel disease. However, the precise mechanisms remain unknown. To determine whether probiotic Lactobacillus plantarum (LP) ameliorates colonic epithelial barrier dysfunction present in interleukin-10 knockout (IL-10-/-) mice, IL-10-/- and wild-type mice received LP or the vehicle for 4 weeks. Colitis was assessed by histological scores and clinical manifestation, and gut paracellular permeability was measured by Ussing chamber. PepT1-mediated transepithelial transport was evaluated by measuring the plasma cephalexin concentration. The expression and distribution of AJC proteins and PepT1 were determined by western blotting and immunofluorescence, and their mRNA by reverse transcriptase-PCR. Spontaneous colitis was observed in all IL-10-/- mice, in which paracellular permeability was increased, in conjunction with decreased expression and redistribution of ZO-1, occludin, claudin-1, and β-catenin. PepT1 expression was increased, accompanied with an enhanced cephalexin transport. Colonic epithelial barrier dysfunction was further confirmed by increased bacterial translocation and proinflammatory cytokine production. Treatment with LP decreased colonic paracellular permeability with restoration of expression and distribution of AJC proteins and partially prevented PepT1 expression and cephalexin transport in IL-10-/- mice. Moreover, treatment with LP also prevented bacterial translocation and proinflammatory cytokine production in IL-10-/- mice. Results from this study indicated that treatment with LP may ameliorate colonic epithelial barrier dysfunction in IL-10-/- mice, by modulating the AJC and PepT1-mediated transepithelial transport.
- Lactobacillus plantarum
- barrier dysfunction
- apical junctional complex
- Copyright © 2010, American Journal of Physiology- Gastrointestinal and Liver Physiology