BACKGROUND: Probiotic bacteria can be used for the prevention and treatment of human inflammatory diseases including inflammatory bowel diseases (IBD). However, the nature of active components and exact mechanisms of this beneficial effects have not been fully elucidated. Our aim was to investigate if lysate of probiotic bacterium L. casei DN-114 001 (Lc) could decrease the severity of intestinal inflammation in a murine model of IBD. METHODOLOGY/PRINCIPAL FINDINGS: The preventive effect of oral administration of Lc significantly reduces the severity of acute dextran sulfate sodium (DSS) colitis in BALB/c but not in SCID mice. In order to analyze how this beneficial effect interferes with well-known phases of intestinal inflammation pathogenesis in vivo and in vitro, we evaluated intestinal permeability using the FITC-labeled dextran method and analysed tight junction proteins expression by immunofluorescence and PCR. We also measured CD4(+)FoxP3(+) regulatory T cells proportion by FACS analysis, microbiota composition by pyrosequencing, and local cytokine production by ELISA. Lc leads to a significant protection against increased intestinal permeability and barrier dysfunction shown by preserved ZO-1 expression. We found that the Lc treatment increases the numbers of CD4(+)FoxP3(+) regulatory T cells in mesenteric lymph nodes (MLN), decreases production of pro-inflammatory cytokines TNF-α and IFN-γ, and anti-inflammatory IL-10 in Peyer's patches and large intestine, and changes the gut microbiota composition. Moreover, Lc treatment prevents lipopolysaccharide-induced TNF-α expression in RAW 264.7 cell line by down-regulating the NF-κB signaling pathway. CONCLUSION/SIGNIFICANCE: Our study provided evidence that even non-living probiotic bacteria can prevent the development of severe forms of intestinal inflammation by strengthening the integrity of intestinal barrier and modulation of gut microenvironment.

• MeSH
• aktivace makrofágů účinky léků   MeSH
• akutní nemoc MeSH
• aplikace orální MeSH
• down regulace účinky léků   MeSH
• fosfoproteiny metabolismus   MeSH
• imunita účinky léků   MeSH
• kolitida mikrobiologie   patologie   patofyziologie   prevence a kontrola   MeSH
• Lactobacillus casei metabolismus   MeSH
• lidé MeSH
• lipopolysacharidy farmakologie   MeSH
• membránové proteiny metabolismus   MeSH
• metagenom účinky léků   MeSH
• myši inbrední BALB C MeSH
• myši SCID MeSH
• myši MeSH
• NF-kappa B metabolismus   MeSH
• permeabilita účinky léků   MeSH
• počet lymfocytů MeSH
• probiotika aplikace a dávkování   farmakologie   MeSH
• regulační T-lymfocyty cytologie   účinky léků   MeSH
• střevní sliznice účinky léků   imunologie   mikrobiologie   MeSH
• TNF-alfa biosyntéza   MeSH
• trávicí systém účinky léků   mikrobiologie   patofyziologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH