Alkaline sphingomyelinase deficiency impairs intestinal mucosal barrier integrity and reduces antioxidant capacity in dextran sulfate sodium-induced colitis

BACKGROUND Ulcerative colitis is a chronic inflammatory disease of the colon with an unknown etiology.Alkaline sphingomyelinase(alk-SMase)is specifically expressed by intestinal epithelial cells,and has been reported to play an anti-inflammatory role.However,the underlying mechanism is still unclear.AIM To explore the mechanism of alk-SMase anti-inflammatory effects on intestinal barrier function and oxidative stress in dextran sulfate sodium(DSS)-induced colitis.METHODS Mice were administered 3%DSS drinking water,and disease activity index was determined to evaluate the status of colitis.Intestinal permeability was evaluated by gavage administration of fluorescein isothiocyanate dextran,and bacterial translocation was evaluated by measuring serum lipopolysaccharide.Intestinal epithelial cell ultrastructure was observed by electron microscopy.Western blotting and quantitative real-time reverse transcription-polymerase chain reaction were used to detect the expression of intestinal barrier proteins and mRNA,respectively.Serum oxidant and antioxidant marker levels were analyzed using commercial kits to assess oxidative stress levels.RESULTS Compared to wild-type(WT)mice,inflammation and intestinal permeability in alk-SMase knockout(KO)mice were more severe beginning 4 d after DSS induction.The mRNA and protein levels of intestinal barrier proteins,including zonula occludens-1,occludin,claudin-3,claudin-5,claudin-8,mucin 2,and secretory immunoglobulin A,were significantly reduced on 4 d after DSS treatment.Ultrastructural observations revealed progressive damage to the tight junctions of intestinal epithelial cells.Furthermore,by day 4,mitochondria appeared swollen and degenerated.Additionally,compared to WT mice,serum malondialdehyde levels in KO mice were higher,and the antioxidant capacity was significantly lower.The expression of the transcription factor nuclear factor erythroid 2-related factor 2(Nrf2)in the colonic mucosal tissue of KO mice was significantly decreased after DSS treatment.mRNA levels of Nrf2-regulated downstream antioxidant enzymes were also decreased.Finally,colitis in KO mice could be effectively relieved by the injection of tertiary butylhydroquinone,which is an Nrf2 activator.CONCLUSION Alk-SMase regulates the stability of the intestinal mucosal barrier and enhances antioxidant activity through the Nrf2 signaling pathway.

Dietary supplementation of bilberry anthocyanin on growth performance,intestinal mucosal barrier and cecal microbes of chickens challenged with Salmonella Typhimurium

Background Anthocyanins(AC)showed positive effects on improving the intestinal health and alleviating intestinal pathogen infections,therefore,an experiment was conducted to explore the protective effects of supplemented AC on Salmonella-infected chickens.Methods A total of 240 hatchling chickens were randomly allocated to 4 treatments,each with 6 replicates.Birds were fed a basal diet supplemented with 0(CON,and ST),100(ACL)and 400(ACH)mg/kg of AC for d 60,and orally challenged with PBS(CON)or 10^(9) CFU/bird(ST,ACL,ACH)Salmonella Typhimurium at d 14 and 16.Results(1)Compared with birds in ST,AC supplementation increased the body weight(BW)at d 18 and the average daily gain(ADG)from d 1 to 18 of the Salmonella-infected chickens(P<0.05);(2)AC decreased the number of Salmonella cells in the liver and spleen,the contents of NO in plasma and inflammatory cytokines in ileal mucosa of Salmonella-infected chickens(P<0.05);(3)Salmonella infection decreased the ileal villi height,villi height to crypt depth(V/C),and the expression of zonulaoccludins-1(ZO-1),claudin-1,occludin,and mucin 2(MUC2)in ileal mucosa.AC supplementation relieved these adverse effects,and decreased ileal crypt depth(P<0.05);(4)In cecal microbiota of Salmonella-infected chickens,AC increased(P<0.05)the alpha-diversity(Chao1,Pd,Shannon and Sobs indexes)and the relative abundance of Firmicutes,and decreased(P<0.05)the relative abundance of Proteobacteria and Bacteroidota and the enrichment of drug antimicrobial resistance,infectious bacterial disease,and immune disease pathways.Conclusions Dietary AC protected chicken against Salmonella infection via inhibiting the Salmonella colonization in liver and spleen,suppressing secretion of inflammatory cytokines,up-regulating the expression of ileal barrier-related genes,and ameliorating the composition and function of cecal microbes.Under conditions here used,100 mg/kg bilberry anthocyanin was recommended.

Puerarin alleviates sleep disorders in aged mice related to repairing intestinal mucosal barrier

More and more evidence suggests that puerarin,a potential remedy for gut inflammation,may have an ameliorative effect on sleep disturbances.However,the relationship between puerarin and sleep disruption has not been extensively researched.This study aims to explore the role and mechanisms of puerarin in improving sleep disorders.We established a light-induced sleep disorder model in mice and assessed the effects of puerarin on cognitive behavior using open field and water maze tests.Pathological detection demonstrated that sleep disturbances resulted in observable damage to the liver,lung,and kidney.Puerarin reversed multi-organ damage and inflammation.Further,puerarin activated paneth cells,resulting in increased lysozyme and TGF-βproduction,and stimulating intestinal stem cell proliferation.Puerarin also effectively inhibited the expression of F4/80,iNOS,TNF-α,and IL-1βin the small intestine,while it increased Chil3,CD206,and Arg-1 levels.Moreover,puerarin treatment significantly decreased P-P65,TLR4,Bcl-xl,and cleaved caspase-3 protein levels while increasing barrier protein levels,including ZO-1,Occludin,Claudin 1 and E-cadherin suggesting a reduction in inflammation and apoptosis in the gut.Overall,puerarin diminished systemic inflammation,particularly intestinal inflammation,and enhanced intestinal barrier integrity in mice with sleep disorders.Our findings suggest a potential new therapeutic pathway for sleep disorders.

Moxibustion regulates inflammatory mediators and colonic mucosal barrier in ulcerative colitis rats

AIM: To observe the efficacy and mechanism of grain-sized moxibustion at different acupoints in a rat model of ulcerative colitis (UC). METHODS: Sprague-Dawley rats were randomly divided into control, UC model, grain-sized moxibustion at a single acupoint (CV 12), grain-sized moxibustion at two acupoints (CV 12 and CV 4), grain-sized moxibustion at three acupoints (CV 12, CV 4, and ST 36), and medication groups (n = 8/group). The UC model was established by enema of trinitrobenzene sulfonic acid. Direct moxibustion was used once a day for 7 d. Disease activity index (DAI) was evaluated before and after the treatment. Morphologic changes of intestinal tissue were observed under an optical microscope. The expression of tumor necrosis factor (TNF)-alpha and p38 mitogen-activated protein kinase (p38MAPK) in colonic tissue was detected using Western blot, and the levels of occludin and zonula occludens-1 (ZO-1) mRNAs were detected using reverse transcription PCR. RESULTS: Compared with the control group, the intestinal mucosae were incomplete in the model group, glandular structures were irregular, and submucosae were edematous, hyperemic, and infiltrated with inflammatory cells. The DAI scores and expression of TNF-alpha and p38MAPK were increased significantly in the model group compared to controls (Ps < 0.01), while the mRNA levels of occludin and ZO-1 were reduced significantly (Ps < 0.01). Compared with the model group, colonic mucosa and the arrangement of glands were complete and regular in the treatment groups. DAI scores and the expression of TNF-alpha and p38MAPK were reduced significantly in moxibustion groups compared to controls (Ps < 0.01), while the mRNA levels of occludin and ZO-1 were increased significantly (Ps < 0.01). The improvements in the above indices in the three acupoints group and the medication group were superior to those in the single and two acupoints groups (all P < 0.05). CONCLUSION: Reduction of TNF-alpha and p38MAPK and increased expression of occludin and ZO-1 in colonic tissue represent a potential mechanism for improved intestinal mucosal tissue repair with grain-sized moxibustion.

Functional changes of intestinal mucosal barrier insurgically critical patients

BACKGROUND： The gut is capable of inducing multiple organ dysfunction syndrome （MODS）. In the diagnosis and treatment of critical ill patients, doctors should pay particular attention to the protection or recovery of intestinal barrier function. However, no reliable diagnostic criteria are available clinically. This study aimed to assess the changes of intestinal mucosal barrier function in surgically critical ill patients as well as their signi？ cance.METHODS： Thirty-eight surgically critical ill patients were enrolled as a study group （APACHE II〉8 scores）, and 15 non-critical ill patients without intestinal dysfunction were selected as a control group （APACHE II〈6）. General information, symptoms, physical signs, and APACHE II scores of the patients were recorded. The patients in the study group were subdivided into an intestinal dysfunction group （n=26） and a non-intestinal dysfunction group （n=12）. Three ml venous blood was collected from the control group on admission and the same volume of plasma was collected from the study group both on admission and in the period of recovery. The plasma concentrations of endotoxin, diamine oxidase （DAO）, D-lactate, and intestinal fatty-acid binding protein （iFABP） were detected respectively. The data collected were analyzed by the SPSS 17.0 software for Windows. RESULTS： The levels of variables were significantly higher in the study group than in the control group （P〈0.01）. They were higher in the intestinal dysfunction group than in the non-intestinal dysfunction group （DAO P〈0.05, endotoxin, D-lactate, iFABP P〈0.01）. In the non-intestinal dysfunction group compared with the control group, the level of endotoxin was not significant （P〉0.05）, but the levels of DAO, D-lactate and iFABP were statistically significant （P〈0.05）. The levels of variables in acute stage were higher than those in recovery stage （P〈0.01）.The death group showed higher levels of variables than the survival group （endotoxin and D-lactate P〈0.01, DAO and iFABP P〈0.05）.CONCLUSION： The plasma concentrations of endotoxin, DAO, D-lactate, and intestinal fatty-acid binding protein （iFABP） could re？ ect a better function of the intestinal mucosa barrier in surgically critical ill patients.

Resveratrol alleviates intestinal mucosal barrier dysfunction in dextran sulfate sodium-induced colitis mice by enhancing autophagy

BACKGROUND Intestinal mucosal barrier dysfunction plays an important role in the pathogenesis of ulcerative colitis(UC).Recent studies have revealed that impaired autophagy is associated with intestinal mucosal dysfunction in the mucosa of colitis mice.Resveratrol exerts anti-inflammatory functions by regulating autophagy.AIM To investigate the effect and mechanism of resveratrol on protecting the integrity of the intestinal mucosal barrier and anti-inflammation in dextran sulfate sodium(DSS)-induced ulcerative colitis mice.METHODS Male C57BL/6 mice were divided into four groups:negative control group,DSS model group,DSS+resveratrol group,and DSS+5-aminosalicylic acid group.The severity of colitis was assessed by the disease activity index,serum inflammatory cytokines were detected by enzyme-linked immunosorbent assay.Colon tissues were stained with haematoxylin and eosin,and mucosal damage was evaluated by mean histological score.The expression of occludin and ZO-1 in colon tissue was evaluated using immunohistochemical analysis.In addition,the expression of autophagy-related genes was determined using reverse transcription-polymerase chain reaction and Western-blot,and morphology of autophagy was observed by transmission electron microscopy.RESULTS The resveratrol treatment group showed a 1.72-fold decrease in disease activity index scores and 1.42,3.81,and 1.65-fold decrease in the production of the inflammatory cytokine tumor necrosis factor-α,interleukin-6 and interleukin-1β,respectively,in DSS-induced colitis mice compared with DSS group(P<0.05).The expressions of the tight junction proteins occludin and ZO-1 in DSS model group were decreased,and were increased in resveratrol-treated colitis group.Resveratrol also increased the levels of LC3B(by 1.39-fold compared with DSS group)and Beclin-1(by 1.49-fold compared with DSS group)(P<0.05),as well as the number of autophagosomes,which implies that the resveratrol may alleviate intestinal mucosal barrier dysfunction in DSS-induced UC mice by enhancing autophagy.CONCLUSION Resveratrol treatment decreased the expression of inflammatory factors,increased the expression of tight junction proteins and alleviated UC intestinal mucosal barrier dysfunction;this effect may be achieved by enhancing autophagy in intestinal epithelial cells.

Diverse expression patterns of mucin 2 in colorectal cancer indicates its mechanism related to the intestinal mucosal barrier

BACKGROUND Abnormal expression patterns of mucin 2(MUC2)have been reported in a variety of malignant tumors and precancerous lesions.Reduced MUC2 expression in the intestinal mucosa,caused by various pathogenic factors,is related to mechanical dysfunction of the intestinal mucosa barrier and increased intestinal mucosal permeability.However,the relationship between MUC2 and the intestinal mucosal barrier in patients with colorectal cancer(CRC)is not clear.AIM To explore the relationship between MUC2 and intestinal mucosal barrier by characterizing the multiple expression patterns of MUC2 in CRC.METHODS Immunohistochemical staining was performed on intestinal tissue specimens from 100 CRC patients,including both cancer tissues and adjacent normal tissues.Enzyme-linked immunosorbent assays were performed on preoperative sera from 66 CRC patients and 20 normal sera to detect the serum levels of MUC2,diamine oxide(DAO),and D-lactate(D-LAC).The relationship between MUC2 expression and clinical parameters was calculated by theχ2 test or Fisher’s exact test.Prognostic value of MUC2 was evaluated by Kaplan-Meier curve and log-rank tests.RESULTS Immunohistochemical staining of 100 CRC tissues showed that the expression of MUC2 in cancer tissues was lower than that in normal tissues(54%vs 79%,P<0.05),and it was correlated with tumor-node-metastasis(TNM)stage and lymph node metastasis in CRC patients(P<0.05).However,the serum level of MUC2 in CRC patients was higher than that in normal controls,and was positively associated with serum levels of human DAO(χ2=3.957,P<0.05)and D-LAC(χ^(2)=7.236,P<0.05),which are the biomarkers of the functional status of the intestinal mucosal barrier.And the serum level of MUC2 was correlated with TNM stage,tumor type,and distant metastasis in CRC patients(P<0.05).Kaplan-Meier curves showed that decreased MUC2 expression in CRC tissues predicted a poor survival.CONCLUSION MUC2 in tissues may play a protective role by participating in the intestinal mucosal barrier and can be used as an indicator to evaluate the prognosis of CRC patients.

Dahuang Fuzi decoction reduces inflammation levels and alleviates intestinal mucosal barrier damage in septic rats

Objective:To investigate the protective effect of Dahuang Fuzi Decoction(DHFZD),a traditional Chinese prescription,at alleviating sepsis-induced inflammation and gut barrier damage in rats.Methods:Forty clean-grade male Sprague-Dawley rats were divided randomly into three groups:normal control group(NCG,n?10),model control group(MCG,n?15)and DHFZD-treated group(DHFZDG,n?15).NCG rats were sham operated on and used as the controls,whereas MCG and DHFZDG rats were used to replicate the rat sepsis model using cecal ligation and puncture(CLP).The DHFZDG rats received DHFZD by gavage(4.5 mg/g of body weight)2 h prior to CLP and after its successful induction,while the NCG and MCG rats received equivalent amounts of sterilized water by gavage.All rat groups were starved and had free access to water.At 24 h post-experimental set up,the mortality of rats in each group was recorded,and peritoneal inflammation assessment and pathological changes related to the intestinal mucosal injury index(IMII)in the surviving rats were evaluated.D-lactic acid,tumor necrosis factor(TNF)-a,interleukin(IL)-6 and IL-10 peripheral blood concentrations,along with secretory immunoglobulin A(sIgA)in the intestinal mucosa were evaluated by enzyme-linked immunosorbent assays.Gut microbes were detected using 16S rRNA gene sequencing.Results:DHFZD reduced sepsis-related mortality in the rats.Moreover,it alleviated peritoneal inflammation and pathological changes according to the IMII.DHFZD reduced serum procalcitonin,TNF-a and IL-6 concentrations,but not the IL-10 concentration.It also reduced serum D-lactic acid and increased sIgA concentrations in intestinal mucosa.Notably,DHFZDG restored gut microbiota diversity and regulated the decrease in Bacteroidetes induced by sepsis,compared with the MCG rats.Conclusion:DHFZDG may play a protective role in sepsis by alleviating sepsis-induced inflammation and gut barrier damage in rats.

Fermentation Production of Ganoderma lucidum by Bacillus subtilis Ameliorated Ceftriaxone-induced Intestinal Dysbiosis and Improved Intestinal Mucosal Barrier Function in Mice

Objective This study aimed to develop a type of Ganoderma lucidum(G.lucidum)-probiotic fermentation broth that can effectively improve the intestinal mucosal barrier function of mice with ceftriaxone-induced intestinal dysbiosis.Methods By means of absorbance of optical density(OD)value and phenol-concentrated sulfuric acid measurement of polysaccharide content,the probiotic species can grow on the medium of G.lucidum were screened out,and the concentration of the medium of G.lucidum was determined,and the fermentation broth was prepared for subsequent experiments.Thirty-two SPF grade male BALB/c mice were randomly divided into four groups(eight mice in each group),namely control group(CON),intestinal mucosal barrier damage model group(CS),fermentation broth intervention group(FT)and G.lucidum medium intervention group(GL),respectively.The intestinal dysregulation model was induced by intra-gastric administration of 0.2 mL ceftriaxone sodium(twice a day for seven consecutive days).From day 8,the FT group and GL group were gavage with 0.2 mL fermentation broth and G.lucidum medium,respectively.On day 15,all mice were sacrificed.To draw the weight curve and measure the cecal index;pathological examination of colon tissues with HE staining;serum levels of LPS,IL-10,TNF and IL-6 were detected by ELISA.Flow cytometry was used to analyze the changes of CD3+T cells,CD4+T cells,CD8+T cells and macrophages in spleen.16S rRNA sequencing was performed to detect the intestinal microbiota structure of mice.Results Bacillus subtilis can decompose and utilize G.lucidum fruiting body medium,and the suitable concentration of G.lucidum fruiting body medium is 33.2 mg/mL.The effect of Bacillus subtilis-G.lucidum fermentation broth on the damage of intestinal mucosal barrier caused by ceftriaxone sodium was reduced,the body weight of mice recovered and colon swelling improved,colon histopathological injury was alleviated,inflammatory cell infiltration was alleviated,serum IL-10 increased significantly,LPS、TNF-αand IL-6 decreased significantly compared with model group,and the proportion of T cells and intestinal dysbiosis was improved.Conclusions The experimental results suggest that Bacillus subtilis-G.lucidum fermentation broth can effectively improve the intestinal barrier function damage,immune dysfunction and intestinal dysbiosis caused by antibiotic overdose,and has a certain regulatory effect on intestinal mucosal barrier function.

Effects of Faecalibacterium prausnitzii intervention on immune response, intestinal flora and intestinal mucosal barrier of mice with ulcerative colitis

Objective: To study the effects of Faecalibacterium prausnitzii intervention on immune response, intestinal flora and intestinal mucosal barrier of mice with ulcerative colitis (UC). Methods: C57BL/6J mice were randomly divided into control group, UC group and Faecalibacterium prausnitzii group, the latter two groups were made into UC models by trinitrobenzene sulfonic acid enema and F. prausnitzii group were given intragastric administration of F. prausnitzii solution for intervention. The differences in immune response, intestinal flora, and intestinal mucosal barrier were compared among the three groups after 7 days of intervention. Results: The interleukin-10 (IL-10) and transforming growth factor-β1 (TGF-β1) contents in serum, the fork head box P3 (Foxp3), zonula occludens-1 (ZO-1), occludin, claudin-1 and claudin-2 expression in intestinal mucosa as well as the number of bifidobacterium and lactobacillus in feces of the UC group were significantly lower than those of the control group whereas the interleukin-17 (IL-17), diamine oxidase (DAO) and D-lactic acid (D-LA) contents in serum, the retinoid-related orphan nuclear receptor γt (RORγt) expression in intestinal mucosa as well as the number of enterobacter and enterococcus in feces were significantly higher than those of the control group (P<0.05);IL-10 and TGF-β1 contents in serum, Foxp3, ZO-1, occludin, claudin-1 and claudin-2 expression in intestinal mucosa as well as the number of bifidobacterium and lactobacillus in feces of the F. prausnitzii group were significantly higher than those of the UC group whereas IL-17, DAO and D-LA contents in serum, RORγt expression in intestinal mucosa as well as the number of enterobacter and enterococcus in feces were significantly lower than those of the UC group (P<0.05). Conclusion: Faecalibacterium prausnitzii intervention can improve the Th17/Treg immune response, intestinal flora and intestinal mucosal barrier in UC mice.

Effects of Estrogen on Mucosal Structure and Numbers and Distribution of Intraepithelial Lymphocytes and Goblet Cells in Small Intestine of Rats

To study the effects of estrogen on the structure of the intestinal mucosal barrier, 18 healthy female Wistar Rats underwent estrus synchronization. In diestrus, they were divided into three groups： one sham operated control group （SHAM） ; one ovariec- tomized group （OVX） ; and one ovariectomized plus estradiol benzoate group （ OVX ＋ E2 ）. Intestinal mu- cosal epithelial cells, intraepithelial lymphocytes （[EL）, and goblet cells （GCs） were observed by light microscope. The results showed that in the OVX group, the intestinal mucosa damaged obviously, the villus atrophied, the ratio of villus height to crypt depth reduced, and the number of IELs and GCs re- duced. The indicators of OVX ＋ Ez group were signif- icantly higher than OVX group, but some indicators were lower than SHAM. These indicated that the function of intestinal mucosal barrier was greatly dam- aged in ovariectomied rat, and proper dosage of estra- diol benzoate Would improve the function of small in- testinal mucosal barrier in ovariectomied rat to some degree.

Intestinal mucosal barrier in functional constipation:Dose it change?

BACKGROUND The intestinal mucosal barrier is the first line of defense against numerous harmful substances,and it contributes to the maintenance of intestinal homeostasis.Recent studies reported that structural and functional changes in the intestinal mucosal barrier were involved in the pathogenesis of several intestinal diseases.However,no study thoroughly evaluated this barrier in patients with functional constipation(FC).AIM To investigate the intestinal mucosal barrier in FC,including the mucus barrier,intercellular junctions,mucosal immunity and gut permeability.METHODS Forty FC patients who fulfilled the Rome IV criteria and 24 healthy controls were recruited in the Department of Gastroenterology of China-Japan Friendship Hospital.The colonic mucus barrier,intercellular junctions in the colonic epithelium,mucosal immune state and gut permeability in FC patients were comprehensively examined.Goblet cells were stained with Alcian Blue/Periodic acid Schiff(AB/PAS)and counted.The ultrastructure of intercellular junctional complexes was observed under an electron microscope.Occludin and zonula occludens-1(ZO-1)in the colonic mucosa were located and quantified using immunohistochemistry and quantitative real-time polymerase chain reaction.Colonic CD3+intraepithelial lymphocytes(IELs)and CD3+lymphocytes in the lamina propria were identified and counted using immunofluorescence.The serum levels of D-lactic acid and zonulin were detected using enzyme-linked immunosorbent assay.RESULTS Compared to healthy controls,the staining of mucus secreted by goblet cells was darker in FC patients,and the number of goblet cells per upper crypt in the colonic mucosa was significantly increased in FC patients(control,18.67±2.99;FC,22.42±4.09;P=0.001).The intercellular junctional complexes in the colonic epithelium were integral in FC patients.The distribution of mucosal occludin and ZO-1 was not altered in FC patients.No significant differences were found in occludin(control,5.76E-2±1.62E-2;FC,5.17E-2±1.80E-2;P=0.240)and ZO-1(control,2.29E-2±0.93E-2;FC,2.68E-2±1.60E-2;P=0.333)protein expression between the two groups.The mRNA levels in occludin and ZO-1 were not modified in FC patients compared to healthy controls(P=0.145,P=0.451,respectively).No significant differences were observed in the number of CD3+IELs per 100 epithelial cells(control,5.62±2.06;FC,4.50±2.16;P=0.070)and CD3+lamina propria lymphocytes(control,19.69±6.04/mm^(2);FC,22.70±11.38/mm^(2);P=0.273).There were no significant differences in serum D-lactic acid[control,5.21(4.46,5.49)mmol/L;FC,4.63(4.31,5.42)mmol/L;P=0.112]or zonulin[control,1.36(0.53,2.15)ng/mL;FC,0.94(0.47,1.56)ng/mL;P=0.185]levels between FC patients and healthy controls.CONCLUSION The intestinal mucosal barrier in FC patients exhibits a compensatory increase in goblet cells and integral intercellular junctions without activation of mucosal immunity or increased gut permeability.

Berberine Enhances Intestinal Mucosal Barrier Function by Promoting Vitamin D Receptor Activity

Objective:To evaluate if berberine can act on vitamin D receptors(VDR)and thereby regulate the expression of tight junction proteins(TJPs)in irritable bowel syndrome-diarrhea-predominant(IBS-D)rats.Methods:The newborn rats were induced into IBS-D rat model via neonatal maternal separation combined with acetic acid chemical stimulation.After modeling,the model was evaluated and rats were divided into the control group and berberine treatment groups(0.85,1.7 and 3.4 mg/kg,once a day for 2 weeks).The distal colon was obtained and colonic epithelial cells(CECs)were isolated and cultured after IBS-D model evaluation.The vitamin D receptor response element(VDRE)reporter gene was determined in the CECs of IBS-D rats to analyze the effect of berberine on the VDRE promoter.VDR overexpression or silencing technology was used to analyze whether VDR plays a role in promoting intestinal barrier repair,and to determine which region of VDR plays a role in berberine-regulated intestinal TJPs.Results:The IBS-D rat model was successfully constructed and the symptoms were improved by berberine in a dose-dependent manner(P<0.05).The activity of VDRE promoter was also effectively promoted by berberine(P<0.05).Berberine increased the expression of TJPs in IBS-D CECs(P<0.05).VDR expression was significantly increased after transfection of different domains of VDR when compared to normal control and basic plasmid groups(all P<0.05).RT-qPCR and Western blot results showed that compared with the blank group,expressions of occludin and zonula occludens-1 were significantly higher in VDR containing groups(all P<0.05).Berberine plus pCMV-Myc-VDR-N group exerted the highest expression levels of occludin and zonula occludens-1(P<0.05).Conclusion:Berberine enhances intestinal mucosal barrier function of IBS-D rats by promoting VDR activity,and the main site of action is the N-terminal region of VDR.

Paeoniflorin ameliorates chronic colitis via the DR3 signaling pathway in group 3 innate lymphoid cells

Inhibiting the death receptor 3(DR3)signaling pathway in group 3 innate lymphoid cells(ILC3s)presents a promising approach for promoting mucosal repair in individuals with ulcerative colitis(UC).Paeoniflorin,a prominent component of Paeonia lactiflora Pall.,has demonstrated the ability to restore barrier function in UC mice,but the precise mechanism remains unclear.In this study,we aimed to delve into whether paeoniflorin may promote intestinal mucosal repair in chronic colitis by inhibiting DR3 signaling in ILC3s.C57BL/6 mice were subjected to random allocation into 7 distinct groups,namely the control group,the 2%dextran sodium sulfate(DSS)group,the paeoniflorin groups(25,50,and 100 mg/kg),the anti-tumor necrosis factor-like ligand 1A(anti-TL1A)antibody group,and the IgG group.We detected the expression of DR3 signaling pathway proteins and the proportion of ILC3s in the mouse colon using Western blot and flow cytometry,respectively.Meanwhile,DR3-overexpressing MNK-3 cells and 2%DSS-induced Rag1^(-/-)mice were used for verification.The results showed that paeoniflorin alleviated DSS-induced chronic colitis and repaired the intestinal mucosal barrier.Simultaneously,paeoniflorin inhibited the DR3 signaling pathway in ILC3s and regulated the content of cytokines(interleukin-17A,granulocyte-macrophage colony stimulating factor,and interleukin-22).Alternatively,paeoniflorin directly inhibited the DR3 signaling pathway in ILC3s to repair mucosal damage independently of the adaptive immune system.We additionally confirmed that paeoniflorin-conditioned medium(CM)restored the expression of tight junctions in Caco-2 cells via coculture.In conclusion,paeoniflorin ameliorates chronic colitis by enhancing the intestinal barrier in an ILC3-dependent manner,and its mechanism is associated with the inhibition of the DR3 signaling pathway.

Critical analysis of the effects of proton pump inhibitors on inflammatory bowel disease:An updated review

This letter critically evaluates the effects of proton pump inhibitors(PPIs)on inflammatory bowel disease,particularly focusing on Crohn's disease(CD)and ulcerative colitis(UC),as discussed in Liang et al’s recent review.While the review provides significant insights,it relies heavily on cross-sectional and observational studies,which limits the ability to draw causal inferences.The heterogeneous study populations and inconsistent definitions of long-term PPI use further complicate the findings.This letter also highlights the need for rigorous control of confounding factors and considers the potential publication bias in the existing literature.The implications of these issues are discussed in the context of both CD and UC,and future research directions are proposed to address these shortcomings.

GSDMD protects intestinal epithelial cells against bacterial infections through its N-terminal activity affecting intestinal immune homeostasis

The intestinal mucosal barrier serves as a vital guardian of the gut health,maintaining a delicate equilibrium between gut microbiota and host immune homeostasis.Gasdermin D(GSDMD),a key executioner of pyroptosis downstream of the inflammasome,has been found to play intricate roles in modulating colitis by influencing intestinal macrophages and regulating mucus secretion from goblet cells.However,the exact nature of the regulatory function of GSDMD in maintaining intestinal immune homeostasis and defending against pathogens remains to be elucidated.In the current study,by using the Citrobacter rodentium infection model,we found that GSDMD played a key role in the defense against intestinal Citrobacter rodentium infection,with high expression levels in intestinal epithelial and lamina propria myeloid cells.Our results showed that GSDMD acted specifically in intestinal epithelial cells to combat the infection,independently of its effects on antimicrobial peptides or mucin secretion.Instead,the resistance was mediated by the N-terminal fragment of GSDMD,highlighting its importance in intestinal immunity.However,the specific mechanism underlying the N-terminal activity of GSDMD in protecting against intestinal bacterial infections requires future investigation.

Protective effect of bone marrow mesenchymal stem cells in intestinal barrier permeability after heterotopic intestinal transplantation

AIM: To explore the protective effect of bone marrow mesenchymal stem cells (BM MSCs) in the small intestinal mucosal barrier following heterotopic intestinal transplantation (HIT) in a rat model.

Effects of Lactobacillus plantarum on gut barrier function in experimental obstructive jaundice

AIM:To investigate the mechanisms of Lactobacillus plantarum(L.plantarum)action on gut barrier in preoperative and postoperative experimental obstructive jaundice in rats.METHODS:Forty rats were randomly divided into groups of sham-operation,bile duct ligation(BDL),BDL +L.plantarum,BDL+internal biliary drainage(IBD),and BDL+IBD+L.plantarum.Ten days after L.plantarum administration,blood and ileal samples were collected from the rats for morphological examination,and intestinal barrier function,liver function,intestinal oxidative stress and protein kinase C(PKC)activity measurement.The distribution and expression of the PKC and tight junction(TJ)proteins,such as occludin,zonula occludens-1,claudin-1,claudin-4,junction adhesion molecule-A and F-actin,were examined by confocal laser scanning microscopy,immunohistochemistry,Western blotting,real-time fluorescent quantitative polymerase chain reaction assay.RESULTS:L.plantarum administration substantially restored gut barrier,decreased enterocyte apoptosis,improved intestinal oxidative stress,promoted the activity and expression of protein kinase(BDL vs BDL+L.plantarum,0.295±0.007 vs 0.349±0.003,P<0.05;BDL+IBD vs BDL+IBD+L.plantarum,0.407±0.046 vs 0.465±0.135,P<0.05),and particularly enhanced the expression and phosphorylation of TJ proteins in the experimental obstructive jaundice(BDL vs BDL+L.plantarum,0.266±0.118 vs 0.326±0.009,P<0.05).The protective effect of L.plantarum was more prominent after internal biliary drainage(BDL+IBD vs BDL +IBD+L.plantarum,0.415±0.105 vs 0.494±0.145,P<0.05).CONCLUSION:L.plantarum can decrease intestinal epithelial cell apoptosis,reduce oxidative stress,and prevent TJ disruption in biliary obstruction by activating the PKC pathway.

Inhibitory effect of water soluble propolis on oxidative damage in rats with ulcerative colitis

Objective:To investigate the effects of water-soluble propolis(WSP)on the levels of colonic mucosal inflammation and oxidative stress in rats with ulcerative colitis(UC).Methods:The UC rat model was made by sodium dextran sulfate(DSS).Forty-eight male rats were randomly divided into six groups:the normal group(N group),the control group(C group),the positive control group(P group),the low-dose propolis group(L group),he medium-dose propolis(M group)and the high-dose propolis group(H group).The protective effect of WSP on DSS induced UC rats was evaluated by preadministration and re-construction model.Body mass,disease activity index(DAI),blood stool,colon length,intestinal mucosal damage index(CMDI)of rats were observed.The indexes of medulla peroxidase(MPO),superoxidase(SOD),malondialdehyde(MDA)and glutathione peroxidase(GSH-Px)in colon tissue were determined by ELISA.Results:the oxidative stress level of colon tissue in the model group was increased and neutrophils were activated.After medium and high concentration propolis intervention,the oxidative stress level was reduced and the colonic inflammatory injury was relieved.Conclusion:WSP can improve the activity of SOD,GSH-Px and other endogenous antioxidant enzymes,reduce oxidative stress products,inhibit the activity of neutrophil and other mechanisms to relieve intestinal inflammation in experimental UC rat model.

Lactobacillus intestinalis/Lactobacillus rhamnosus protects against AFB_(1)-induced liver damage:involvement of intestinal mucosal barrier

Aflatoxin B1(AFB1)is a widely spread mycotoxin that poses a threat to the healthy to human and animals.The liver is the main target organ for AFB1-induced damage,primarily causing inflammatory injury and oxidative stress.When AFB1 enters the body,it can damage the intestinal barrier function,and its metabolites are transported to the liver.Therefore,the damage to the liver is closely associated with intestinal barrier impairment.Lactobacillus plays a crucial role in mitigating liver damage by improving the intestinal barrier function.In our previous report,we reported that Lactobacillus reduces liver damage caused by AFB1.However,it is still unclear how the intestinal barrier contributes to the protective effects of Lactobacillus against AFB1.To investigate the protective effects and intestinal barrier mechanisms of Lactobacillus intestinals/rhamnosus against AFB1-induced liver damage,we orally administered AFB1 and Lactobacillus intestinals/rhamnosus to male SD rats.Then the body weight,organ index,histopathological changes in the liver and gut,liver and kidney function indicators,intestinal mucosal barrier indicators,serum AFB1 content and inflammatory factors,liver oxidative stress index,and short-chain fatty acids content were analyzed.Our findings demonstrate that exposure to AFB1 resulted in changes in liver histopathology and biochemical functions,altered inflammatory response and oxidative stress,compromised the intestinal mucosal barrier,and induced the accumulation of inflammatory factor and inflammation in the liver.However,supplementation with Lactobacillus intestinals or Lactobacillus rhamnosus significantly prevented AFB1-induced liver injury,alleviated histopathological changes and hepatic injury by the maintenance of intestinal mucosal barrier integrity.