Galactooligosaccharides protects against DSS-induced murine colitis through regulating intestinal flora and inhibiting NF-κB pathway

Background/aims: Previous studies have demonstrated that Galactooligosaccharides (GOS), known as "bifidus factor", has anti-inflammatory effects. Colitis, a kind of colonic inflammatory damage could be induced by different chemicals. The pathogenesis and mechanism of colitis remains unclear, and may be related to intestinal microflora, genetic susceptibility or immune factors. The aim is to explore the effects of GOS on intestinal flora and its anti-inflammatory effects in Dextran Sulfate Sodium (DSS) induced murine colitis and extrapolate the underlying mechanism. Main methods: Initially, 5% DSS was used to induced colitis by free access to drinking water for 5-7 days. Then the mice were treated with GOS 1 day after DSS treatment. Colon samples were evaluated grossly using a microscope. The percentage of Treg and Th17 cells was analyzed by flow cytometry. The levels of cytokines secretion and mRNA expression were detected by ELISA and real-time PCR. The level of protein was detected by western blot. Key findings: GOS attenuated DSS induced body weight loss and also reduced the increase in disease index caused by DSS. GOS ameliorated DSS induced colonic histological damage. The protective effect of GOS on DSS induced colitis may be partly attributed to intestinal flora regulation and Th17/Treg imbalance. Furthermore, GOS markedly decreased cytokines (IL-6, IL-18, IL-13 and IL-33) secretion and mRNA expression in colon tissues, through inhibiting activation of NF-kappa B pathways. Significance: GOS could prevent the DSS induced colitis through intestinal flora regulation and reduce the secretion of inflammation related cytokines relying on the NF-kappa B signaling pathway.