基于脑肠轴探究半夏泻心汤对DSS-UC小鼠肠道菌群及5-HT的影响

The Effects of Banxia Xiexin Decoction on Gut Microbiota and 5-HT in DSS-UC Mice were Investigated Based on Brain-Gut Axis

目的观察半夏泻心汤对采用葡聚糖硫酸钠(Dextran sulfate sodium,DSS)自由饮用诱导建立的溃疡性结肠炎(Ulcerative colitis,UC)模型小鼠肠道微生物及5-HT的影响,从脑肠轴角度分析半夏泻心汤治疗UC的作用机制。方法将40只C57BL6/J雄性小鼠随机分为空白组、模型组、阳性药(美沙拉嗪)组及半夏泻心汤组,除空白组外的各小鼠采用2.5%DSS水溶液自由饮用7天诱导建立UC小鼠模型。自实验第8天起,分别采用灭菌水、美沙拉嗪水溶液、半夏泻心汤水溶液给上述各组别小鼠灌胃。采用HE染色观察结肠组织病理学变化,ELISA方法检测血清、结肠及脑组织中5-HT含量,16S rRNA测序技术进一步检测模型小鼠粪便中菌群的变化。结果经半夏泻心汤干预后,与模型组比较,实验组小鼠较模型组小鼠的DAI指数显著降低(P<0.05);抑炎因子IL-2、IL-4及致炎因子IFN-γ水平均有显著恢复(P<0.05);结肠近端及远端病理组织学评分亦均有显著降低(P<0.01);外周5-HT水平显著降低(P<0.05),中枢5-HT水平有升高趋势;Clostridium_sensu_stricto_1、unclassified_p__Firmicutes相对丰度升高(P<0.05),Lachnospiraceae_NK4A136_group、Lachnoclostridium、norank_f__Oscillospiraceae、Eubacterium_xylanophilum_group相对丰度降低(P<0.05)。同时研究发现,众多肠道微生物菌属与机体外周及中枢5-HT水平存在显著相关性。结论半夏泻心汤可以通过改善UC小鼠肠道微生物组成结构,以降低外周5-HT水平、升高中枢5-HT水平,进而改善肠道炎症反应、缓解焦虑情绪,从而发挥治疗溃疡性结肠炎的作用。

Objective To observe the effects of Banxia Xiexin Decoction on intestinal microbes and 5-HT in ulcerative colitis(UC)model mice induced by drinking sodium dextran sulfate(DSS),and to analyze the mechanism of Banxia Xiexin Decoction in treating UC from the perspective of brain-gut axis.Methods 40 male C57BL6/J mice were randomly divided into control group,model group,positive drug(mesalazine)group and Banxia Xiexin decoction group.All mice except control group were induced by 2.5%DSS solution for 7 days to establish UC model.From the 8th day,mice in the above groups were given intragastric administration of sterilized water,mesalazine aqueous solution and Banxia Xiexin decoction aqueous solution.HE staining was used to observe histopathological changes of colon,ELISA to detect 5-HT content in serum,colon and brain tissues,and 16S rRNA sequencing to further detect the changes of fecal flora in model mice.Results Compared with model group,DAI index of experimental mice model group was significantly decreased after Banxia Xiexin Decoction intervention(P<0.05);IL-2,IL-4 and IFN-γ were significantly recovered(P<0.05).The histopathological score of proximal and distal colon was significantly decreased(P<0.01).Moreover,the peripheral 5-HT level was significantly decreased(P<0.05),but the central had an increasing trend.Results of intestinal flora showed that the relative abundance of Clostridium_sensu_stricto_1,unclassified_p__Firmicutes increased(P<0.05),while Lachnospiraceae_NK4A136_group,Lachnoclostridium,norank_f__Oscillospiraceae and Eubacterium_xylanophilum_group decreased(P<0.05).It was also found that there were significant correlations between intestinal microflora and peripheral and central 5-HT levels.Conclusion Banxia Xiexin Decoction could play a role in treating ulcerative colitis by improving the intestinal microbial composition structure of UC mice to reduce peripheral 5-HT levels and increase central 5-HT levels,thereby improving intestinal inflammatory response and relieving anxiety.