title: Lactobacillus reuteri maintains a functional mucosal barrier during DSS treatment despite mucus layer dysfunction.
abstract: Treatment with the probiotic bacterium Lactobacillus reuteri has been shown to prevent dextran sodium sulfate (DSS)-induced colitis in rats. This is partly due to reduced P-selectin-dependent leukocyte- and platelet-endothelial cell interactions, however, the mechanism behind this protective effect is still unknown. In the present study a combination of culture dependent and molecular based T-RFLP profiling was used to investigate the influence of L. reuteri on the colonic mucosal barrier of DSS treated rats. It was first demonstrated that the two colonic mucus layers of control animals had different bacterial community composition and that fewer bacteria resided in the firmly adherent layer. During DSS induced colitis, the number of bacteria in the inner firmly adherent mucus layer increased and bacterial composition of the two layers no longer differed. In addition, induction of colitis dramatically altered the microbial composition in both firmly and loosely adherent mucus layers. Despite protecting against colitis, treatment with L. reuteri did not improve the integrity of the mucus layer or prevent distortion of the mucus microbiota caused by DSS. However, L. reuteri decreased the bacterial translocation from the intestine to mesenteric lymph nodes during DSS treatment, which might be an important part of the mechanisms by which L. reuteri ameliorates DSS induced colitis.
authors.affiliation: Department of Microbiology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Uppsala, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Dicksved
authors.forename: Olof
authors.initials: O
authors.lastname: Schreiber
authors.forename: Ben
authors.initials: B
authors.lastname: Willing
authors.forename: Joel
authors.initials: J
authors.lastname: Petersson
authors.forename: Sara
authors.initials: S
authors.lastname: Rang
authors.forename: Mia
authors.initials: M
authors.lastname: Phillipson
authors.forename: Lena
authors.initials: L
authors.lastname: Holm
authors.forename: Stefan
authors.initials: S
authors.lastname: Roos
mesh_terms: D000818:Animals; D058491:Bacterial Load; D018988:Bacterial Translocation; D003092:Colitis / Q000139:chemically induced / Q000382:microbiology / Q000473:pathology / Q000517:prevention & control*; D003106:Colon / Q000187:drug effects / Q000382:microbiology* / Q000473:pathology; D016264:Dextran Sulfate; D007413:Intestinal Mucosa / Q000382:microbiology / Q000473:pathology; D052200:Limosilactobacillus reuteri / Q000502:physiology*; D008297:Male; D054892:Metagenome / Q000235:genetics*; D009093:Mucus / Q000187:drug effects / Q000378:metabolism / Q000382:microbiology*; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D019936:Probiotics / Q000008:administration & dosage / Q000627:therapeutic use*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D012336:RNA, Ribosomal, 16S; D016264:Dextran Sulfate