OBJECTIVE To investigate the mechanism of Huangqin decoction in improving ulcerative colitis （UC） through the gut microbiota-tryptophan metabolism-aryl hydrocarbon receptor （AhR） axis. METHODS Mice were randomly divided into normal group （normal saline）， model group （normal saline）， microbiota depletion-model group （normal saline）， microbiota depletion-Huangqin decoction group （9.1 g/kg， by crude drug， similarly hereinafter）， Huangqin decoction group and mesalazine group （positive control group， 0.4 g/kg）， with 6 mice in each group. Microbiota depletion was achieved by providing free access to a mixed antibiotics for 10 days. The UC model was induced by administering 2.5% dextran sulfate sodium solution for 7 days. After successful modeling， each treatment group received corresponding drugs or normal saline intragastrically once daily for 10 days. After the final administration， body weight change ratio， disease activity index （DAI） score， and colon length were evaluated； colon pathological changes were observed； serum levels of interleukin-6 （IL-6）， IL-10， IL-22， and tumor necrosis factor-α （TNF-α） were measured； the expressions of Occludin， zonula occluden-1 （ZO-1）， and AhR in colon tissue were detected； fecal samples were subjected to high-throughput sequencing to analyze targeted tryptophan metabolomics. RESULTS Compared with the model group， Huangqin decoction group showed reduced infiltration of inflammatory cells in the colon tissue and restoration of the intestinal mucosal structure. Body weight change ratio， colon length， serum content of IL-10， the expressions of Occludin， ZO-1 and AhR in colon tissue and the contents of tryptophan metabolites indole-3-propionic acid （IPA）， N -acetylserotonin （NAS） and indole-3-acetic acid （IAA） were all significantly increased （ P ＜0.05）； DAI score， serum levels of IL-6， TNF-α， and IL-22 and the content of tryptophan metabolite indole-3-ethanol were significantly decreased （ P ＜0.05）； gut microbiota structure was improved， with increased relative abundances of beneficial bacteria such as Lactobacillus ， and decreased relative abundances of pathogenic bacteria such as Escherichia-Shigella . However， after antibiotic-induced microbiota depletion， although Huangqin decoction significantly increased the content of NAS in the feces of mice， the expression of AhR protein in colon tissue did not increase concurrently. CONCLUSIONS Huangqin decoction can repair the intestinal mucosal barrier in UC mice by regulating the gut microbiota and promoting the production of IPA and IAA， thereby activating AhR. This suggests that an intact gut microbiota is an important prerequisite for Huangqin decoction to exert its AhR-regulating effects.

Irritable bowel syndrome(IBS)is a kind of gastrointestinal dysfunction disease characterized by abdominal pain and abnormal defecation accompanied by changes in frequency or fecal character as the main clinical symptoms,and diarrhea-type irritable bowel syndrome(IBS-D)is the most common.It has been found that Chinese medicine therapy has achieved good results in the treatment of IBS-D through multi-component,multi-target and multi-pathway targeted regulation of intestinal flora.Therefore,based on intestinal flora,this paper reviews the relationship between intestinal flora and IBS-D,the understanding of Chinese medicine on IBS-D and intestinal flora,and the role of Chinese medicine therapy on intestinal flora.

Irritable bowel syndrome(IBS)is a kind of gastrointestinal dysfunction disease characterized by abdominal pain and abnormal defecation accompanied by changes in frequency or fecal character as the main clinical symptoms,and diarrhea-type irritable bowel syndrome(IBS-D)is the most common.It has been found that Chinese medicine therapy has achieved good results in the treatment of IBS-D through multi-component,multi-target and multi-pathway targeted regulation of intestinal flora.Therefore,based on intestinal flora,this paper reviews the relationship between intestinal flora and IBS-D,the understanding of Chinese medicine on IBS-D and intestinal flora,and the role of Chinese medicine therapy on intestinal flora.

OBJECTIVE To investigate the effects of Tongxie yaofang （TXYF） on the symptoms of rats with irritable bowel syndrome with diarrhea （IBS-D） by regulating colonic tryptophan hydroxylase 1 （TPH1）， serotonin transporter （SERT） and intestinal flora. METHODS Forty-two SD rats were randomly divided into control group （7 rats） and modeling group （35 rats）. In modeling group， rat model of IBS-D was established by intragastrical administration of 0.45 g/L senna leaf solution [10 mL/（kg·d）] combined with chronic unpredictable stimulation. Thirty-five successfully modeled rats were randomly divided into model group， pinaverium bromide group [15 mg/（kg·d）] and TXYF low-dose， medium-dose and high-dose groups [3.75、7.5、15 g/（kg·d）， calculated by crude drug]， with 7 rats in each group. Each administration group was orally administered the corresponding drug， once a day， for 10 consecutive days. The general condition and weight changes of each group of rats were compared before modeling， after modeling and before administration， after the last drug intervention； the diarrhea index and visceral sensitivity were detected， and pathological changes of colon tissue were observed after modeling and before administration， after the last drug intervention. The level and expression of 5-hydroxytryptamine （5-HT）， protein and mRNA expressions of TPH1 and SERT were determined in colon tissue. The diversity and structural changes of fecal intestinal flora of rats were analyzed. RESULTS There was no significant change in colon histopathology in each group. Compared with model group， the general condition of rats in each medication group improved. The daily body weight gain of rats was significantly increased， while diarrhea index， visceral sensitivity， the expressions of 5-HT and TPH1 in colon tissue were significantly decreased； SERT expression of colon tissue was significantly increased in TXYF medium-dose and high-dose groups （P＜0.05 or P＜0.01）. The diarrhea index， colon TPH1 protein expression and colon 5-HT protein positive rate in the TXYF low-dose group decreased while the mRNA expression of SERT increased significantly （P＜0.05）. There was a dose- dependent trend in the effect of TXYF. Compared with model group， Chao1 index and Shannon index of the rats in TXYF high- dose group were significantly decreased （P＜0.05 or P＜0.01）， the beneficial bacteria such as Firmicutes and Lactobacillus increased significantly， while the pathogenic bacteria such as Proteobacteria， Escherichia-Shigella and Rikenellaceae_RC9_gut_ group decreased significantly （P＜0.05 or P＜0.01）. CONCLUSIONS TXYF can decrease the level of 5-HT and improve intestinal flora disorder by inhibiting the expression of TPH1 and up-regulating the expression of SERT in colon tissue， thus promoting the symptoms of IBS-D rats.

OBJECTIVE：To inves tigate the application effect and safety of modified compound polyethylene glycol electrolyte powder（SF-PEG）in intestinal preparation method for patients with constipation undergoing colonoscopy. METHODS ：From Jan. 2020 to Aug. 2020，160 patients with constipation undergoing colonoscopy in anorectal department of the affiliated hospital of North Sichuan Medical College were randomly divided into observation group and control group ，with 80 cases in each group. The patients in the control group took 2 boxes of SF-PEG （mixed into 3 000 mL warm water ）orally at 3：00 a.m. on the day of examination，and finished within 2 hours. The patients in the observation group took 1 box of SF-PEG （mixed into 1 500 mL warm water）at 20：00 the night before the examination and 5：00 in the morning of the day of examination ，and drank it within 1 hour；1 bottle of Dimethylsiloxane powder （mixed into 75 mL warm water ）was taken orally at 7：00 a.m. on the inspection day. The satisfaction of intestinal preparation ，intestinal bubble score ，operation time of colonoscopy ，detection of polyps ，tolerance rate ， acceptance rate of repeating intestinal preparation of patients and incidence of adverse reactions were compared between the two groups. RESULTS ：The patients of 2 groups successfully completed bowel preparation and colonoscopy. The intestinal preparation total satisfaction rate ，intestinal bubble satisfaction rate ，polyp detection rate ，tolerance rate and repeating intestinal preparation acceptance rate of patients of observation group were significantly higher than control group （P＜0.05），while the incidence of nausea and vomiting and total incidence of adverse reactions were significantly lower than control group （P＜0.05），and the operation time of colonoscopy was significantly shorter than control group （P＜0.05）. CONCLUSIONS ：Oral administration of SF-PEG in batches combined with Dimethylsiloxane powder for bowel preparation in patients with constipation before colonoscopy have the advantages of high satisfaction with bowel preparation ，less intestinal bubbles ，short operation time ，high detection rate of polyps，high tolerance rate of patients ，high acceptance rate of repeating intestinal preparation and less adverse reactions. It is a safe and effect method for intestinal preparation.