ABSTRACT
BACKGROUND/AIMS: The current study aims to investigate the protective effects of Bifidobacterium infantis on the abnormal immune response to inflammatory bowel disease (IBD) in dextran sodium sulfate (DSS)-induced colitis. METHODS: Eight-week-old BALB/c mice were separated into five groups at random (control, DSS, DSS+B9 [B. infantis 1×10⁹ CFU], DSS+B8 [B. infantis 1×10⁸ CFU], and DSS+B7 [B. infantis 1×10⁷ CFU]). Colitis was induced by 5% DSS ad libitum for 7 days, at which time we assessed weight, the disease activity index (DAI) score, and the histological damage score. The nuclear transcription factor Foxp3 (a marker of Treg cells), cytokines interleukin-10 (IL-10) and transforming growth factor β1 (TGF-β1), and related proteins (programmed cell death ligand 1 [PD-L1] and programmed cell death 1 [PD-1]) were detected by an immunohistochemical method and Western blot. RESULTS: B. infantis increased weight, decreased DAI scores and histological damage scores, increased the protein expression of Foxp3 (p<0.05) and cytokines IL-10 and TGF-β1 in mouse colon tissue (p<0.05), and increased the expression of PD-L1 in the treatment groups relative to that in the DSS group (p<0.05). The effect of B. infantis on Foxp3 and PD-L1 was dose dependent in the treatment groups (p<0.05). PD-L1 was positively correlated with Foxp3, IL-10, and TGF-β1. CONCLUSIONS: In a mouse model of IBD, B. infantis can alleviate intestinal epithelial injury and maintain intestinal immune tolerance and thus may have potential therapeutic value for the treatment of immune damage in IBD.
Subject(s)
Animals , Mice , Bifidobacterium , Blotting, Western , Cell Death , Colitis , Colon , Cytokines , Dextrans , Immune Tolerance , Inflammatory Bowel Diseases , Interleukin-10 , Methods , Models, Theoretical , Sodium , T-Lymphocytes, Regulatory , Transcription Factors , Transforming Growth FactorsABSTRACT
Objective To establish the inflammatory bowel disease model of mice by Trinitro-benzenesulfonic acid(TNBS).To investigate the correlation between the IBD and SIgA level and the effect of Clostridium butyricum,Bifidobacterium infantis single or combined on sIgA expression.Methods BABL/c mice were randomly divided into:WT group,TNBS group,CB group,BB group and CB + BB group.After 2 weeks,the general situation and weight change of mice was evaluated.Then the mice were sacrificed to collect colon tissue.The inflammation of each group was observed by HE staining.The expression of sIgA were respectively located and measured by immunohistochemistry and Western blotting.Results TNBS group showed more pathological changes in the colon than the WT group,CB group,BB group and CB + BB group;the expressions of sIgA in colon were mainly located in intestinal lumen and lamina propria of intestinal villus;the level of sIgA in colon and tissue decreased in the TNBS group compared with WT group(P ＜ 0.01;P ＜ 0.01);the level of sIgA in colon and tissue increased ín the CB group and BB group compared with TN-BS group(P ＜0.01;P ＜0.01;P ＜0.01;P ＜ 0.01).There is no significant difference between CB group and BB group(P ＞ 0.05).The level of sIgA in colon and tissue increased in the CB +BB group compared with CB group or BB group(P ＜0.01;P ＜0.01).Conclusion The change of sIgA content is related to the occurrence of IBD.CB and BB can both promote sIgA production in IBD mice and reduce the inflammatory reaction.The combination of the two probiotics shows stronger effect than single one.
ABSTRACT
Objective:To investigate whether diethyldithiocarbamate (DDC) affect the activity of superoxide dismutase (SOD) of Bifidobacterium infantis ( BB ) .Methods: We used simple anaerobic activated ways to culture BB .After the bacterium reached platform growth period ,two concentrations (200 and 1 000 μmol/L) of DDC were added to bacterium medium for a specific period of time (0.5,1,2,4 and 24 h),which was in order to determine if this inhibitor affected the activity of SOD .As a positive control,the in-hibitory effect of DDC on the activity of SOD in murine intestinal samples was also checked .Results:It was found that incubation of BB with DDC for some specific periods showed no effect on the activity of SOD .However , the activity of SOD in intestine reduced dramatically after the mice were given DDC in vivo .Conclusion:DDC affect the SOD activity in mice ,while it showed no effect on SOD activity of BB.The suitable inhibitor for SOD of BB is not commercially available and further research is warranted .
ABSTRACT
Objective To analyze the roles and mechanisms of lactitol and Bifidobacterium infantis in the treatment of rat constipation and to investigate their effects on aquaporin3 (AQP3) and interstitial cells of Cajal (ICC) in colon tissues.Methods Thirty SD male rats were recruited in this study,6 of which were randomly selected as the control and the rest were given 4 mg/kg.d of loperamide for 5 consecutive days to construct the rat model of constipation.The rats with constipation were randomly divided into four groups including model group,lactitol treatment group,Bifidobacterium infantis treatment group and lactitol in combination with Bifidobacterium infantis treatment group.General indexes including food intake,water intake,body weight,fecal water content and intestinal transit rate of each rat were measured after receiving corresponding treatments for 7 consecutive days.The levels of substance P (SP) and vasoactive intestinal peptide (VIP) in serums samples were detected by ELISA.The expression of protein kinase A (PKA) and neurokinin-1 receptor (NK-1) at mRNA level in colon tissues were detected by real-time polymerase chain reaction (real-time PCR).Western blot assay and real-time PCR analysis were used to detect the expression of AQP3 and c-kit at protein and mRNA levels,respectively.Results Compared with the rats in model group,the levels of fecal water content and intestinal transit rate,the concentrations of SP and VIP in serums samples,the expression of PKA and NK-1 at mRNA level and the expression of AQP3 and c-kit at mRNA and protein levels were significantly increased in rats from the three treatment groups (P＜0.05).The most effective treatment was lactitol in combination with Bifidobacterium infantis,followed by the lactitol treatment and then the Bifidobacterium infantis treatment.Conclusion The combination therapy with lactitol and Bifidobacterium infantis increased the serum levels of SP and VIP in rats with constipation.SP could enhance the contraction of gastrointestinal smooth muscles and improve the intestinal motility by binding to the NK-1 receptor on the membrane of ICC.VIP could promote the absorption of water in intestinal tracts,soften stools and alleviate constipation by upregulating the expression of AQP3 at both protein and mRNA levels via the cyclic adenosine monophosphate-PKA (cAMP-PKA) signaling pathway.