Ulcerative colitis (UC) is the most common inflammatory bowel disease (IBD); it is incurable, and the treatment is expensive. Trans-anethole (TA), the main component of fennel, exhibits various biological activities. An increasing number of studies have demonstrated the efficacy of herbal active ingredients in the treatment of UC. This study aimed to investigate the effect and mechanism of TA in UC. In this study, we have experimented on mice with dextran sulfate sodium salt (DSS)-induced UC. The TA group was gavaged with 62.5 mg/kg TA by gavage once daily on days 8–14. To observe the effect of TA on the colon tissue, various investigations were performed, including western blot and immunohistochemistry for intestinal barrier protein expression, TUNEL staining for apoptosis, western blot, and ELISA for inflammation level, flow cytometry for Th17/Treg, LC–MS for blood bile acid content, GC–MS for blood fatty acid content, and 16s RNA for intestinal contents. TA alleviated weight loss in mice with UC; increased colon length; alleviated intestinal mucosal damage; upregulated claudin-1, occludin, and ZO-1 protein expression levels; reduced inflammatory factors in the colon and serum; and alleviated apoptosis. TA reduced fatty acid and bile acid levels by inhibiting colony abundance and reducing Th17/Treg cell differentiation in the colon. We found that TA alleviates DSS-induced UC by remodeling the intestinal flora to regulate immunity and bile acid metabolism.

中文翻译：

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反式茴香脑通过重塑肠道菌群调节免疫和胆汁酸代谢来减轻 DSS 诱发的溃疡性结肠炎

溃疡性结肠炎 (UC) 是最常见的炎症性肠病 (IBD)；这是无法治愈的，而且治疗费用昂贵。反式茴香脑（TA）是茴香的主要成分，具有多种生物活性。越来越多的研究证明了草药活性成分在治疗 UC 方面的功效。本研究旨在探讨TA在UC中的作用及机制。在这项研究中，我们在小鼠身上进行了实验，用葡聚糖硫酸钠 (DSS) 诱导 UC。TA组在第8-14天每天灌胃一次62.5 mg/kg TA。为了观察TA对结肠组织的影响，进行了各种研究，包括免疫印迹和免疫组化检测肠屏障蛋白表达、TUNEL染色检测细胞凋亡、免疫印迹和ELISA检测炎症水平、流式细胞术检测Th17/Treg、LC- MS 用于测定血液胆汁酸含量，GC-MS 用于测定血液脂肪酸含量，16s RNA 用于测定肠道内容物。TA 减轻了 UC 小鼠的体重减轻；结肠长度增加；减轻肠粘膜损伤；上调claudin-1、occludin 和 ZO-1 蛋白表达水平；减少结肠和血清中的炎症因子；并减轻细胞凋亡。TA 通过抑制结肠中集落丰度和减少 Th17/Treg 细胞分化来降低脂肪酸和胆汁酸水平。我们发现TA通过重塑肠道菌群来调节免疫和胆汁酸代谢来减轻DSS诱导的UC。