Gut dysbiosis and bile acid (BA) metabolism disturbance are involved in the pathogenesis of ulcerative colitis. This study aimed to investigate the effect of fucoidan on BA metabolism and gut microbiota in dextran sulfate sodium-induced colitis mice. Our results showed that fucoidan effectively suppressed colonic inflammation and repaired the gut barrier. In addition, fucoidan increased the relative abundance of the Lachnospiraceae family, such as Turicibacter, Muribaculum, Parasutterella, and Colidextribacter, followed by an increase in short-chain fatty acids, especially in butyrate. Moreover, fucoidan modulated bile acid metabolism by elevating cholic acid, ursodeoxycholic acid, deoxycholic acid, and lithocholic acid and decreasing β-muricholic acid, which led to activation of FXR and TGR5 and further enhanced the gut barrier and suppressed colonic inflammation. Our results revealed that the effect of fucoidan alleviating colitis was largely mediated by gut microbiota, which was confirmed by the fecal transplantation experiment. Collectively, these findings provided the basis for fucoidan as a potential functional food for colitis.

中文翻译：

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褐藻糖胶通过调节肠道菌群和胆汁酸代谢改善葡聚糖硫酸钠诱导的溃疡性结肠炎

肠道菌群失调和胆汁酸 (BA) 代谢紊乱与溃疡性结肠炎的发病机制有关。本研究旨在探讨褐藻糖胶对葡聚糖硫酸钠诱导的结肠炎小鼠 BA 代谢和肠道菌群的影响。我们的结果表明，褐藻糖胶有效抑制结肠炎症并修复肠道屏障。此外，褐藻糖胶增加了毛螺菌科的相对丰度，例如Turicibacter、Muribaculum、Parasutterella和Colidextribacter，其次是短链脂肪酸的增加，尤其是丁酸。此外，岩藻依聚糖通过升高胆酸、熊去氧胆酸、脱氧胆酸和石胆酸并降低β-鼠胆酸来调节胆汁酸代谢，从而导致FXR和TGR5的激活并进一步增强肠道屏障并抑制结肠炎症。我们的结果表明，褐藻糖胶缓解结肠炎的作用主要由肠道微生物群介导，粪便移植实验证实了这一点。总的来说，这些发现为褐藻糖胶作为结肠炎的潜在功能性食品提供了基础。