Study On The Effect Of Sodium Houttuyfonate On Ulcerative Colitis Under Overcolonization Of Candidaalbicans Based On Gut Microflora

Objective:The aim of this study was to investigate Sodium houttuyfonate（SH）to restore intestinal flora by inhibiting the overgrowth of Candida albicans in the intestine,thereby reducing intestinal dysfunction in mice with ulcerative colitis（UC）.Methods:In a mouse model of colitis induced by dextran sulfate sodium（DSS）infected by C.albicans,the effects of SH on oxidative stress,inflammation and intestinal mucosal barrier integrity were observed in non-cohousing and cohousing models.Non-cohousing experiment:C57BL/6 mice were randomly divided into sham-operation（Sham）group,DSS group,DSS＿CA group,SH20 group and Fluconazole（FLU）group.From day 1 to day 11,the Sham group drank water freely while the DSS group drank 2.5%DSS freely.The DSS＿CA group was fed with C.albicans SC5314strain suspension(1×10⁸CFU mouse^-1)on the 1st,3rd,5th and 7th day,and drank 2.5%DSS continuously from the 1st to 11th day.C.albicans and DSS were given to mice in SH 20 group and FLU group at the same time,and 20 mg kg^-1SH or 2 mg m L^-1FLU were given by gavage on the 7th to 11th day.Cohousing experiment:C57BL/6 mice were randomly divided into Sham group,PBS＿S group,PBS＿CO group,SH20＿CO group and SH20＿S group.In the first week,all groups of mice were given gastric water（Sham group）,PBS（PBS group）or SH20 mg kg^-1（SH20 group）;In the second week,During the second week,the PBS-treated mice and the SH-treated mice were housed singly or co-housed;In the third week,all the mice in the other groups drank 2.5%DSS freely,and C.albicans suspension(1×10⁸CFU mouse^-1)was given on the 1st,3rd,5th and 7th day.The dietary intake,body weight,disease activity index（Disease Activity Index,DAI）,colon length,fungal load in feces and organs（liver,spleen,kidney,stomach,brain,colon）,serum oxidative factors（LPS,MDA,MPO）,and inflammatory factors（TNF-α,IL-1β,IL-6 and IL-10）in serum and colon were measured in non-cohousing and cohousing UC mice.Detection of intestinal tight junction proteins（ZO-1,Occludin and Claudin-1）.In addition,the 16S rRNA of mouse fecal microbiome was analyzed by high-throughput DNA sequencing to evaluate the effect of SH on intestinal microflora of UC mice in non-cohousing and cohousing mode.Results:Compared with C.albicans infected UC mice,SH could significantly improve the dietary intake and body weight of UC mice,reduce DAI,increase the length of colon,reduce the fungal load in feces and organs,reduce the content of serum oxidizing factors（LPS,MDA and MPO）,improve the abnormal protein levels of inflammatory factors（TNF-α,IL-1β,IL-6 and IL-10）in serum and colon,and increase the expression of intestinal tight junction proteins（ZO-1,Occludin and Claudin-1）.By 16S rRNA gene sequencing,C.albicans interference caused intestinal microbiota dysbiosis accompanying with an increase of some harmful pathogens including Klebsiella and Bacteroides.In contrast,SH could modulate the abundance and diversity of microbiota with an elevation of several beneficial bacteria comprising short-chain fatty acid-producing bacteria（Lachnospiraceae＿NK4A136＿group,Intestinimonas）and probiotics（Lactobacillus,Alloprevotella）.In addition,using the transmission characteristics of intestinal flora,we observed that SH played an anti-UC role by reducing intestinal sensitivity to C.albicans and improving intestinal flora through cohabitation experiment.Compared with the PBS＿S mice,the cohabitation mice（PBS＿CO and SH20＿CO）were less sensitive to C.albicans exacerbation of colitis,and the effects of dietary intake,body weight,DAI,colon length and fungal load,oxidation factors,inflammation and intestinal mucosal integrity were similar to those of UC mice treated with SH alone.Through 16S rRNA gene sequencing,it was found that the abundance of harmful bacteria（Bacteroides）decreased and the abundance of beneficial bacteria（Lactobacillus,g＿Eutonum＿siraeum＿group and g＿Alloprevotea）increased significantly after cohabitation.Conclusion:SH can improve intestinal flora homeostasis by inhibiting intestinal overgrowth of C.albicans,thereby improving UC intestinal function.