Protective Effect Of Fructooligosaccharides On Intestinal Mucosal Barrier In Mice With Inflammatory Bowel Disease

Objective:Inflammatory bowel disease(IBD)is a chronic gastrointestinal inflammatory disease with complex etiology.Crohn ’s disease(CD)and ulcerative colitis(UC)are the two most common subtypes.Although the exact cause of IBD remains unknown,it is generally believed that diet plays a key role in the development of IBD.Diet shapes the composition of the gut microbiota,which uses nutrients obtained from the diet to grow and settle in the intestine.The imbalance of human intestinal microecological balance is one of the most common pathogenesis of IBD,including CD and UC,which showed intestinal flora disorder and mucosal damage.At present,dietary therapy is more and more concerned by people.Dietary fiber in food is considered to promote the growth of intestinal beneficial bacteria,maintain the microecological balance of intestinal flora,and repair intestinal mucosal damage.Therefore,the purpose of this study was to explore the protective mechanism of soluble dietary fiber fructooligosaccharides on intestinal mucosal barrier in IBD mice,and to provide a new theoretical basis for the pathogenesis and clinical treatment of IBD.Methods:1.Dose measurement : IBD mouse model was established by dextran sulfate sodium(DSS)induction,and C57 BL / 6 mice were randomly divided into 5 groups : control group(CON),model group(DSS),low dose group(LD),medium dose group(MD)and high dose group(HD).The model group was given free drinking of 4 % DSS aqueous solution,the low-dose group was given drinking distilled water containing 4 % DSS,and10 mg / ml SDF was given daily for 7 days.The middle dose group and the high dose group were given 20 mg / ml and 30 mg / ml respectively by gavage.The control group did not do any intervention treatment,and the mice were given normal drinking water,and other feeding conditions were consistent.The body weight,fecal traits and hematochezia of mice were monitored daily.2.Treatment options : C57 BL / 6 mice were randomly divided into 5 groups : control group(CON),model group(DSS),isomaltooligosaccharide group(IMO),fructooligosaccharide group(FOS),polydextrose group(PDX).The mice in the control group drank distilled water normally every day,the model group drank 4 % DSS aqueous solution freely,and the isomaltooligosaccharide group was given 20 mg / ml concentration of IMO by gavage for 7 days.The FOS group and the PDX group were given FOS and PDX by gavage at a concentration of 20 mg / ml,and other feeding conditions were the same.The body weight,fecal traits and hematochezia of mice were monitored daily.3.The protective effect of fructooligosaccharides on intestinal mucosal barrier in IBD mice : 6-8 weeks C57 BL / 6 mice were randomly divided into 3 groups : control group(CON)drinking distilled water;the model group(DSS)was fed with distilled water containing 4 % DSS for 7 days.The fructooligosaccharides intervention group(FOS)was given 20 mg / ml fructooligosaccharides aqueous solution by gavage for 7days while DSS induction.The body weight,fecal traits and hematochezia of mice were monitored daily,and the Disease Activity Index(DAI)score was calculated.After the experiment,the mice were sacrificed,and the colon length of each group was counted.HE staining was used to observe the pathological changes of colon tissue in mice.Real-time fluorescence quantitative PCR was used to analyze the relative expression of tight junction protein ZO-1,Claudin-1 and Occludin gene m RNA.Western Blot and immunofluorescence staining were used to observe the expression levels of ZO-1,Claudin-1 and Occludin proteins in the intestine of each group to detect the function of intestinal mechanical barrier.Results:1.Compared with the low and high dose groups,the body weight and DAI score of the middle dose group decreased significantly compared with the model group(P< 0.05).This shows that the medium dose(20mg / ml)of SDF has the best effect on alleviating colonic mucosal injury in mice.2.Compared with the IMO and PDX groups,the mice in the FOS group had significantly better effects in relieving colitis symptoms(P< 0.05).Therefore,the best choice for SDF to treat IBD mice is FOS.3.FOS intake can significantly increase the body weight of IBD mice,relieve diarrhea,hematochezia and colon tissue damage,and reduce DAI score,the differences were statistically significant(P< 0.05);compared with the blank control group,the relative expression of ZO-1,Claudin-1,Occludin protein and its gene m RNA in the colon of the model group was significantly decreased.Compared with the model group,the expression levels of ZO-1,Claudin-1,Occludin protein and its gene m RNA in the colon of mice in the FOS intervention group were significantly increased,and the difference was statistically significant(P< 0.05).This shows that FOS can significantly improve the expression of tight junction proteins and protect the intestinal mucosal barrier of IBD mice.Conclusion:1.The best choice for SDF treatment of IBD mice is FOS,and the appropriate dose is 20 mg / ml.2.FOS intervention can alleviate the symptoms of colitis in IBD mice and reduce the degree of colonic mucosal injury.3.FOS intervention can up-regulate the expression of colonic tight junction proteins ZO-1,Claudin-1 and Occludin,and has a protective effect on intestinal mucosal barrier in IBD mice.