IDDF2024-ABS-0389 Polysaccharides from bupleurum ameliorates dextran sulfate sodium-induced colitis by modulating the gut microbiota in mice

<h3>Background</h3> Ulcerative colitis (UC) is a common subtype of inflammatory bowel disease (IBD) in clinical practice. The incidence is increasing year by year in Asia. As an ingredient of Chinese medicine, bupleurum has been used for more than two thousand years. In recent years, polysaccharides have attracted much attention due to their wide range of biological activities, such as anti-inflammatory, antioxidant, anti-tumor, etc. However, the therapeutic effect of bupleurum polysaccharides (BP) on intestinal inflammation has not been investigated. The aim of this study was to evaluate the therapeutic effect of BP on dextran sulfate sodium (DSS)-induced colitis (UC) mice and to explore the underlying mechanisms. <h3>Methods</h3> Colitis was induced in mice by administrating DSS in drinking water for 5 days. BP (200 mg/kg) was administered by gavage 3 times after molding. Colon pathological change was estimated by H&amp;E staining; protein level of inflammatory cytokines was measured by ELISA assay; expression of the tight junction was evaluated by immunohistochemistry (IHC); and intestinal flora changes were measured by 16S sequencing. <h3>Results</h3> The results showed that BP treatment significantly ameliorated UC mice by decreasing loss of weight, increasing colon length and improving pathological characteristics. Besides, BP treatment significantly suppressed the protein levels of pro-inflammatory cytokines, including IL-6 and MPO, and increased anti-inflammatory cytokine IL-10.SOD content was also increased by BP, as shown in figure 1 (IDDF2024-ABS-0389 Figure 1. BP could modulate the gut flora). Furthermore, BP also protects the intestinal barrier by increasing the protein expression of zonula occludens-1 (ZO-1) and occludin. The 16S sequencing revealed that BP treatment increased flora richness and the intestinal flora structure was obviously changed. Especially, <i>erysipelatocloclotridium</i> was increased, <i>turicibacter, romboutsia</i> and <i>sphingomonas</i> were decreased by BP, as shown in figure 2 (IDDF2024-ABS-0389 Figure 2. The therapeutic effect of BP in UC mice). <h3>Conclusions</h3> In conclusion, our findings have demonstrated that BP could improve DSS-induced intestinal inflammation by regulating the gut microbiota.