The Screening And Efficacy Evaluation Of Lactobacillus With Irritable Bowel Syndrome And Ulcerative Colitis Alleviating Effects

Irritable bowel syndrome(IBS)and ulcerative colitis(UC)are two common intestinal diseases in modern society,greatly impacting health and quality of life.Various IBS and UC treatments such as drugs and dietary can cause many side effects while relieving the disease.The regulation of IBS and UC pathogenesis by Lactobacillus is a new way to cure the diseases.However,not all Lactobacillus strains can effectively alleviate the symptoms of IBS and UC,which indicated that the alleviating effect of probiotics on IBS and UC is strain-specific.This strain-specific may be due to the difference in physiological characteristics and functional genes.But the key physiological characteristics and functional genes of probiotics in alleviating IBS and UC are still unknown.Therefore,this study took Lactobacillus as the research object,established the IBS and UC animal models,explored the potential efficacy of Lactobacillus in alleviating IBS and UC,and analyzed the key physiological characteristics and functional genes of Lactobacillus in alleviating IBS and UC.Finally,the effects of Lactobacillus plantarum CCFM8610,a Lactobacillus strain with excellent IBS and UC alleviating effects,on IBS and UC patients were explored.Firstly,an IBS model was established by subjecting C57BL/6 mice to Citrobacter rodentium infection and water avoidance stress exposure.Meanwhile,8 Lactobacillus strains were administered to mice intragastrically.Indicators of colonic inflammation,visceral hypersensitivity,and gut microbiota were evaluated,and significant differences in IBSalleviating effects between Lactobacillus strains were observed.The results showed that most strains did not alleviate the symptoms of IBS.Among the 8 tested Lactobacillus strains,only L.plantarum CCFM8610 significantly restored colonic histopathological damage,inhibited the expression of TNF-?,IL-6,PAR-2,and mast cell tryptase,increased the intestinal barrier function,reduced the score of abdominal withdrawal reflex,inhibited visceral hypersensitivity symptoms,and modulated the gut microbiota diversity and composition.However,the ingestion of Lactobacillus casei CCFM30 and L.casei VM3 was shown to exacerbate colonic inflammation in mice.No significant IBS-alleviating effects were found in other strains.This evidence confirmed the strain specificity of Lactobacillus strain in alleviating IBS.To create animal models,UC was established in C57BL/6 mice by adding the dextran sulfate sodium in the drinking water.And the UC-alleviating effects of 8 dietary intervention Lactobacillus strains on the indicators of basic physiological and biochemical,colonic inflammation,and gut microbiota were also evaluated.The results showed that there was a great difference in the UC-alleviating effects of Lactobacillus.L.casei M2S01,L.plantarum N13,and L.plantarum CCFM8610 showed preliminary UC-alleviating effects on UC,as observed by the restoration of body weight,the disease activity index(DAI)score,and the colonic pathological damage in mice.However,the efficacy of the three strains is still different.L.plantarum CCFM8610 and L.plantarum N13 could decrease the expression of several proinflammatory cytokines(such as IL-6 and TNF-?),while L.casei M2S01 significantly increased the expression of anti-inflammatory cytokines(IL-10 and IL-22).L.plantarum CCFM8610 and L.casei M2S01 can recover the gut microbiota diversity.L.plantarum CCFM8610 had the best effect on modulating the gut microbiota composition.This evidence confirmed the strain specificity of Lactobacillus strain in alleviating UC.No significant UCalleviating effects were found in other strains.After verifying the strain specificity of IBS and UC alleviating effects in Lactobacillus,6physiological characteristics related to IBS and UC were determined by the in vitro microbiological experiments.And the functional genes of 8 Lactobacillus strains were also detected by comparative genomic analysis.The results indicated that in addition to the acetic acid production,8 Lactobacillus strains have significant differences in other 5 physiological characteristics.In terms of functional genes,the L.plantarum CCFM8610 was quite different.The L.plantarum CCFM8610 genome contained a significantly higher number of genes related to 10 primary functions,including amino acid transport and metabolism,when compared with the other tested strains.After annotated by the Clusters of orthologous groups(COG)database,it was found that L.plantarum CCFM8610 differed significantly from the other strains in 14 COGs.This finding indicates that L.plantarum CCFM8610 might exhibit different physiological characteristics and functions relative to other strains.Furthermore,matrix analysis was constructed by R language,and the Pearson correlation coefficients were used to quantify the correlations between the physiological characteristics,functional genes,and IBS,UC alleviating effects of Lactobacillus strains.The results showed that the ability to synthesize conjugated linoleic acid(CLA)might be the key physiological characteristic of Lactobacillus in IBS and UC alleviation.Lipid transport and metabolism,amino acid transport and metabolism,and nucleotide transport and metabolism were identified as the most relevant Lactobacillus genomic indicators associated with IBS and UC alleviating effects.After combining this result with 14 differential COGs,it can be identified that genes related to COG1028 were the most strongly associated functional genes to IBS and UC alleviating effects.COG1028 is associated with lipid transport and metabolism and is annotated as a member of the short-chain alcohol dehydrogenase family according to the National Center for Biotechnology Information(NCBI,www.ncbi.nlm.nih.gov).Short-chain alcohol dehydrogenase is considered necessary to the ability of L.plantarum to transform CLA.Therefore,it can be speculated that L.plantarum CCFM8610 benefits from an abundance of genes related to COG1028,which can confer an excellent ability to synthesize CLA.Based on this,L.plantarum CCFM8610 can effectively alleviate IBS and UC.Finally,in order to verify the IBS and UC alleviating effects of L.plantarum CCFM8610,patients with IBS-D and UC were recruited,and dietary intervention was carried out with L.plantarum CCFM8610.The clinical symptoms,quality of life,and gut microbiota dysbiosis of the patients were investigated.Compared with placebo,the results showed that L.plantarum CCFM8610 could significantly alleviate bloating,improve bowel habit satisfaction,quality of life,and gut microbiota dysbiosis.In addition,L.plantarum CCFM8610 can also improve the erythrocyte sedimentation rate and C-reactive protein in UC patients,thus reducing the activity of UC and alleviating the symptoms of UC.These results indicated that L.plantarum CCFM8610 is a Lactobacillus strain with significant IBS and UC alleviating effects.