Lactobacillus reuteri maintains a functional mucosal barrier during DSS treatment despite mucus layer dysfunction

PLoS One. 2012;7(9):e46399. doi: 10.1371/journal.pone.0046399. Epub 2012 Sep 27.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacterial Load
  • Bacterial Translocation
  • Colitis / chemically induced
  • Colitis / microbiology
  • Colitis / pathology
  • Colitis / prevention & control*
  • Colon / drug effects
  • Colon / microbiology*
  • Colon / pathology
  • Dextran Sulfate
  • Intestinal Mucosa / microbiology
  • Intestinal Mucosa / pathology
  • Lactobacillus reuteri / physiology*
  • Male
  • Metagenome / genetics*
  • Mucus / drug effects
  • Mucus / metabolism
  • Mucus / microbiology*
  • Phylogeny
  • Polymorphism, Restriction Fragment Length
  • Probiotics / administration & dosage
  • Probiotics / therapeutic use*
  • RNA, Ribosomal, 16S / genetics
  • Rats
  • Rats, Sprague-Dawley


  • RNA, Ribosomal, 16S
  • Dextran Sulfate

Grant support

The study was supported by grants from the Swedish Research Council (04X-08646, 57P-20680-01-4, 57x-20675-01-4),; Swedish Research Council for Environment, Agricultural Science and Spatial Planning (222-2006-454),; Nanna Svartz Foundation,; Ruth and Richard Julins Foundation,; and Biogaia AB Stockholm, Sweden, The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.