背景:香连丸(XLP),传统的中国配方,在中国被广泛用作溃疡性结肠炎(UC)的治疗。然而,其治疗作用机制尚不清楚。
目的:我们以前的研究表明,口服生物利用度低,主要XLP成分在肠道中的主要分布。在本研究中,我们旨在从肠道微生态调节方面探讨XLP对UC的作用机制。
方法:用XLP处理5%葡聚糖硫酸钠建立UC模型大鼠。治疗期后,体重,结肠长度,组织病理学,和炎症变化进行评估。Further,通过16SrRNA测序检测到肠道菌群结构的变化,通过代谢组学分析分析粪便中的微生物代谢产物。还采用抗生素干预和粪便微生物群移植来探索肠道微生物群的参与。同时通过流式细胞术测定肠系膜淋巴结中调节性T细胞(Tregs)的水平。还进行转录组测序以确定结肠基因变化。
结果:XLP减轻了结肠损伤,炎症,UC模型大鼠的肠道微生物菌群失调,也改变了微生物代谢产物的水平。特别是,它显著降低了酪氨酸途径中的琥珀酸水平。我们还观察到来自XLP处理的大鼠的粪便微生物群赋予UC模型大鼠恢复力。然而,XLP对UC的这种治疗作用被琥珀酸抑制.此外,XLP通过肠道微生物群增加抗炎细胞Tregs的水平。然而,琥珀酸盐的补充抵消了这种有益效果.Further,XLP可能通过降低微生物琥珀酸产生来调节PHD2/HIF-1α途径诱导Treg的分化。
结论:我们的研究结果表明,XLP主要通过肠道菌群-琥珀酸-Treg分化轴发挥其对UC的治疗作用。
BACKGROUND: Xianglian pill (XLP), a traditional Chinese formula, is widely used as treatment for ulcerative colitis (UC) in China. However, the mechanism of its therapeutic effect is still unclear.
OBJECTIVE: Our previous studies showed a low oral bioavailability and a predominant distribution of major XLP ingredients in the gut. In the present study, we aimed to explore the mechanism of action of XLP on UC with respect to the regulation of gut microecology.
METHODS: UC model rats established using 5% dextran sulfate sodium were treated with XLP. After the treatment period, bodyweight, colon length, histopathology, and inflammatory changes were evaluated. Further, changes in gut microbiota structure were detected via 16S rRNA sequencing, and microbial metabolites in feces were analyzed via a metabolomic assay. Antibiotic intervention and fecal microbiota transplantation were also employed to explore the involvement of gut microbiota, while the level of regulatory T cells (Tregs) in mesenteric lymph nodes was determined via flow cytometry. Transcriptome sequencing was also performed to determine colonic gene changes.
RESULTS: XLP alleviated colonic injury, inflammation, and gut microbial dysbiosis in UC model rats and also changed microbial metabolite levels. Particularly, it significantly decreased succinate level in the tyrosine pathway. We also observed that fecal microbiota derived from XLP-treated rats conferred resilience to UC model rats. However, this therapeutic effect of XLP on UC was inhibited by succinate. Moreover, XLP increased the level of anti-inflammatory cellular Tregs via gut microbiota. However, this beneficial effect was counteracted by succinate supplementation. Further, XLP induced the differentiation of Treg possibly by the regulation of the PHD2/HIF-1α pathway via decreasing microbial succinate production.
CONCLUSIONS: Our findings indicated that XLP exerts its therapeutic effects on UC mainly via the gut microbiota-succinate-Treg differentiation axis.