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.

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.

Protective effect of exogenous IGF-I on the intestinal mucosal barrier in rats with severe acute pancreatitis

BACKGROUND:Severe acute pancreatitis(SAP) can result in intestinal mucosal barrier(IMB)dysfunction.This study was undertaken to demonstrate the effect of IGF-I on the intestinal mucosal barrier in rats with SAP and its possible mechanisms.METHODS:Seventy-two male Wistar rats were randomly divided into three groups:a sham operation(SO group,n=24),a SAP group not treated with IGF-I(SAP group,n=24),and a SAP group treated with IGF-I(IGF-I group,n=24).SAP was induced in the rats by injecting 5.0%sodium taurocholate into the biliary-pancreatic duct.The SO rats were given an infusion of normal saline instead.The rats in the IGF-I group underwent the SAP procedure and were given a subcutaneous injection of IGF-I at 30 minutes before the operation and at 3 hours after the operation.Eight rats in each group were sacrificed at 6,12 and 24 hours after operation.Apoptosis of mucosal cells in the small intestine was determined by TUNEL.The levels of endotoxin and DAO and serum amylase were also measured.Pathologic changes in the small intestine were monitored.Changes of bax and bcl-2 mRNA expression in the small intestine were determined by reverse transcription polymerase chain reaction(RT-PCR).RESULTS:The levels of serum amylase were lower in the IGF-I group than in the SAP group at all three time points(P<0.05).The levels of endotoxin in the IGF-I group were higher than those in the SAP group at 6 hours,but lower in the IGF-I group than in the SAP group at 12 and 24 hours(P<0.05).The levels of diamine oxidase were higher in the IGF-I group at 6 hours but lower than those in the SAP group at 12 and 24 hours.The pathological score of the small intestine was lower in the IGF-I group than in the SAP group,and the difference was statistically significant at 12 and 24 hours.The pathologic changes observed under electron microscopy were better in the IGF-I group than those in the SAP group.The apoptosis index of intestinal epithelial cells was significantly decreased in the IGF-I group compared with the SAP group.Compared with the SO group,the mRNA expression levels of bax were increased at each time point in the SAP group,and were significantly decreased in the IGF-I group as compared with the SAP group at each time point(P<.05).The expression levels of bcl-2 were weak and not different between the SO group and the SAP group(P>0.05).They were significantly increased in the IGF-I group versus the SO and SAP groups(P<0.05).The ratio of bax and bcl-2 mRNA expression levels at each time point in the SAP group were significantly higher than those in the SO group,but they were obviously decreased in the IGF-I group.CONCLUSIONS:Exogenous IGF-I seems to protect mucosal cells in the small intestine against SAP-induced apoptosis and could alleviate SAP-induced injury of the intestinal mucosa.The underlying mechanisms include enhanced mRNA expression of bcl-2 and inhibition of bax mRNA expression.

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.

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.

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.

Rhubarb Monomers Protect Intestinal Mucosal Barrier in Sepsis via Junction Proteins

Background： Leakage of the intestinal mucosal barrier may cause translocation of bacteria, then leading to multiorgan lhilure. This study hypothesized that rhubarb monomers might protect the gut mucosal barrier in sepsis through junction proteins. Methods： Healthy male Sprague-Dawley rats （weighing 230-250 g） tinder anesthesia and sedation were subjected to cecal ligation and perforation （CLP）. After surgical preparation, rats were randornly assigned to eight groups （n = 6 or 8 each group）： sham group （Group A： normal saline gavage）; sepsis group （Group B： nomlal saline gavage）; Group C （intraperitoneally, dexamethasone 0.5 mg/kg） immediately after CLP surgery; and rhubarb monomer （ 100 mg/kg in normal saline）-treated groups （Group D： rhein： Group E： emodin; Group F： 3,8-dihydroxy- l-methyl-anthraquinone-2-carboxylic acid; Group G： 1-O-caffeoyl-2-（4-hydroxy-O-cinnamoyl）-D-glucose; and Group H： daucosterol linoleate）. Animals were sacrificed after 24 h. Intestinal histology, lactulose, mannito[ concentrations were measured, and zonula occludens （ZO）-I, occludin and claudin-5 transcription （polymerase chain reaction）, translation （by Western blot analysis）, and expression （by immunohistochemistry） were also measured. Results： Intestinal histology revealed injury to intestinal mucosal villi induced by sepsis in Group B, compared with Group A. Compared with Group A （0.17 ± 0.41 ）, the pathological scores in Groups B （2.83 ± 0.41, P 〈 0.001）, C （ 1.83 ± 0.41, P 〈 0.001 ）, D （2.00 ± 0.63, P 〈 0.001）, E （ 1.83 ± 0.41, P 〈 0.001 ）, F （ 1.83 ± 0.75, P 〈 0.001 ）, G （2.17 ± 0.41, P 〈 0.001 ）,and H （ 1.83 ± 0.41, P 〈 0.001 ） were significantly increased. Lactulose/mannitol （L/M） ratio in Group B （0.046 ± 0.003） was significantly higher than in Group A （0.013 ± 0.001, P 〈 0.001） while L/M ratios in Groups C （0.028 ± 0.002, P 〈 0.001 ）, D （0.029 ± 0.003, P 〈 0.001 ）, E （0.026 ± 0.003, P 〈 0.001 ）, F （0.027 ± 0.003, P 〈 0.001 ）, G （0.030 ± 0.005, P 〈 0.001 ）, and H （0.026 ± 0.002, P 〈 0.001 ） were significantly lower than that in Group B. ZO- 1, occludin and claudin-5 transcription, translation, and expression in Group B were significantly lower than that in Group A （P 〈 0.001 ）, but they were significantly higher in Groups C, D, E, F, G, and H than those in Group B （P 〈 0.05）. Conclusion： Rhubarb monomer treatment ameliorated rnucosal damage in sepsis via enhanced transcription, translation, and expression of junction proteins.

Heat stress-induced mucosal barrier dysfunction is potentially associated with gut microbiota dysbiosis in pigs

Heat stress(HS)can be detrimental to the gut health of swine.Many negative outcomes induced by HS are increasingly recognized as including modulation of intestinal microbiota.In turn,the intestinal microbiota is a unique ecosystem playing a critical role in mediating the host stress response.Therefore,we aimed to characterize gut microbiota of pigs’exposure to short-term HS,to explore a possible link between the intestinal microbiota and HS-related changes,including serum cytokines,oxidation status,and intestinal epithelial barrier function.Our findings showed that HS led to intestinal morphological and integrity changes(villus height,serum diamine oxidase[DAO],serum D-lactate and the relative expressions of tight junction proteins),reduction of serum cytokines(interleukin[IL]-8,IL-12,interferongamma[IFN-g]),and antioxidant activity(higher glutathione[GSH]and malondialdehyde[MDA]content,and lower superoxide dismutase[SOD]).Also,16S rRNA sequencing analysis revealed that although there was no difference in microbial a-diversity,some HS-associated composition differences were revealed in the ileum and cecum,which partly led to an imbalance in the production of short-chain fatty acids including propionate acid and valerate acid.Relevance networks revealed that HS-derived changes in bacterial genera and microbial metabolites,such as Chlamydia,Lactobacillus,Succinivibrio,Bifidobacterium,Lachnoclostridium,and propionic acid,were correlated with oxidative stress,intestinal barrier dysfunction,and inflammation in pigs.Collectively,our observations suggest that intestinal damage induced by HS is probably partly related to the gut microbiota dysbiosis,though the underlying mechanism remains to be fully elucidated.

Interferon-β induced in female genital epithelium by HIV-1 glycoprotein 120 via Toll-like-receptor 2 pathway acts to protect the mucosal barrier

More than 40%of HIV infections occur via female reproductive tract(FRT)through heterosexual transmission.Epithelial cells that line the female genital mucosa are the first line of defense against HIV-1 and other sexually transmitted pathogens.These sentient cells recognize and respond to external stimuli by induction of a range of carefully balanced innate immune responses.Previously,we have shown that in response to HIV-1 gp120,the genital epithelial cells(GECs)from upper reproductive tract induce an inflammatory response that may facilitate HIV-1 translocation and infection.In this study,we report that the endometrial and endocervical GECs simultaneously induce biologically active interferon-β(IFNβ)antiviral responses following exposure to HIV-1 that act to protect the epithelial tight junction barrier.The innate antiviral response was directly induced by HIV-1 envelope glycoprotein gp120 and addition of gp120 neutralizing antibody inhibited IFNβproduction.Interferon-βwas induced by gp120 in upper GECs through Toll-like receptor 2 signaling and required presence of heparan sulfate on epithelial cell surface.The induction of IFNβwas dependent upon activation of transcription factor IRF3(interferon regulatory factor 3).The IFNβwas biologically active,had a protective effect on epithelial tight junction barrier and was able to inhibit HIV-1 infection in TZM-bl indicator cells and HIV-1 replication in T cells.This is the first report that recognition of HIV-1 by upper GECs leads to induction of innate antiviral pathways.This could explain the overall low infectivity of HIV-1 in the FRT and could be exploited for HIV-1 prophylaxis.

Mechanism of Shengmai Injection on Anti-Sepsis and Protective Activities of Intestinal Mucosal Barrier in Mice

Objective:To study the mechanism of Shengmai Injection(SMI)on anti-sepsis and protective activities of intestinal mucosal barrier.Methods:The contents of 11 active components of SMI including ginsenoside Rb1,Rb2,Rb3,Rd,Re,Rf,Rg1,Rg2,ophioposide D,schisandrol A and schisantherin A were determined using ultra-performance liquid chromatography.Fifty mice were randomly divided into the blank,the model,the low-,medium-and high-dose SMI groups(0.375,0.75,1.5 mL/kg,respectively)by random number table,10 mice in each group.On SMI group,SMI was administrated to mice daily via tail vein injection for 3 consecutive days,while the mice in the blank and model groups were given 0.1 mL of normal saline.One hour after the last SMI administration,except the blank group,the mice in other groups were intraperitoneally injected with lipopolysaccharide(LPS)saline solution(2 mL/kg)at a dosage of 5 mL/kg for development of endotoxemia mice model.The mice in the blank group were given the same volume of normal saline.Inflammatory factors including interferon-γ(INF-γ),tumor necrosis factor-α(TNF-α),interleukin(IL)-2 and IL-10 were measured by flow cytometry.Myosin light-chain kinase(MLCK),nuclear factorκB(NF-κB)levels,and change of Occludin proteins in jejunum samples were analyzed by Western blot.Results:The decreasing trends of INF-γ,TNF-α and IL-2 were found in serum of SMI treatment groups.In SMI-treated mice,the content of Occludin increased and MLCK protein decreased compared with the model group(P<0.05 or P<0.01).The content of cellular and nuclear NF-κB did not change significantly(P>0.05).Conclusion:SMI may exert its anti-sepsis activity mainly through NF-κB-pro-inflammatory factor-MLCK-TJ cascade.

Mucosal healing and inflammatory bowel disease:Therapeutic implications and new targets

Mucosal healing(MH)is vital in maintaining homeostasis within the gut and protecting against injury and infections.Multiple factors and signaling pathways contribute in a dynamic and coordinated manner to maintain intestinal homeostasis and mucosal regeneration/repair.However,when intestinal homeostasis becomes chronically disturbed and an inflammatory immune response is constitutively active due to impairment of the intestinal epithelial barrier autoimmune disease results,particularly inflammatory bowel disease(IBD).Many proteins and signaling pathways become dysregulated or impaired during these pathological conditions,with the mechanisms of regulation just beginning to be understood.Consequently,there remains a relative lack of broadly effective therapeutics that can restore MH due to the complexity of both the disease and healing processes,so tissue damage in the gastrointestinal tract of patients,even those in clinical remission,persists.With increased understanding of the molecular mechanisms of IBD and MH,tissue damage from autoimmune disease may in the future be ameliorated by developing therapeutics that enhance the body’s own healing response.In this review,we introduce the concept of mucosal healing and its relevance in IBD as well as discuss the mechanisms of IBD and potential strategies for altering these processes and inducing MH.

Carbon monoxide-releasing molecule-2 protects intestinal mucosal barrier function by reducing epithelial tight-junction damage in rats undergoing cardiopulmonary resuscitation

Background:Ischemia-reperfusion injury(IRI)to the small intestine is associated with the development of systemic inflammation and multiple organ failure after cardiopulmonary resuscitation(CPR).It has been reported that exogenous carbon monoxide(CO)reduces IRI.This study aimed to assess the effects of carbon monoxide-releasing molecule-2(CORM-2)on intestinal mucosal barrier function in rats undergoing CPR.Methods:We established a rat model of asphyxiation-induced cardiac arrest(CA)and resuscitation to study intestinal IRI,and measured the serum levels of intestinal fatty acid-binding protein.Morphological changes were investigated using light and electron microscopes.The expression levels of claudin 3(CLDN3),occludin(OCLN),zonula occludens 1(ZO-1),tumor necrosis factor-alpha(TNF-α),interleukin-10(IL-10),and nuclear factor kappa B(NF-κB)p65 were detected by western blotting.Results:Compared with the sham-operated group,histological changes and transmission electron microscopy revealed severe intestinal mucosal injury in the CPR and inactive CORM-2(iCORM-2)groups.In contrast,CORM-2 alleviated intestinal IRI.CORM-2,unlike iCORM-2,markedly decreased the Chiu’s scores(2.38±0.38 vs.4.59±0.34;P<0.05)and serum intestinal fatty acid-binding protein level(306.10±19.22 vs.585.64±119.84 pg/mL;P<0.05)compared with the CPR group.In addition,CORM-2 upregulated the expres-sion levels of tight junction proteins(CLDN3,OCLN,and ZO-1)(P<0.05)and downregulated those of IL-10,TNF-α,and NF-кB p65(P<0.05)in the ileum tissue of rats that received CPR.Conclusions:CORM-2 prevented intestinal mucosal damage as a result of IRI during CPR.The underlying protective mechanism was associated with inhibition of ischemia-reperfusion-induced changes in intestinal epithelial permeability and inflammation in intestinal tissue.

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.

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.

Advances of nanoparticles in transmucosal drug delivery

Transmucosal drug administration represents a potential strategy for enhancing treatment efficacy and reducing side effects by avoiding the first-pass effect into the systemic circulation and delivering therapeutics directly to the target disease site.However,many challenges still remain in its clinical application,including low drug availability and limited retention time in the mucosa.The burgeoning advancement of nanotechnologies offers great potential to overcome the above limitations,leveraging their distinct advantages of high drug-loading capacity and strong permeability.In this review,the latest developments of nanoparticles(NPs)in transmucosal drug delivery as well as their clinical applications are discussed.

Effects of permissive hypocaloric vs standard enteral feeding on gastrointestinal function and outcomes in sepsis

BACKGROUND Intestinal mucosal barrier injury and gastrointestinal dysfunction are important causes of sepsis.However,few studies have investigated the effects of enteral underfeeding on gastrointestinal function in sepsis.Moreover,no consensus on goal enteral caloric intake has been reached in sepsis.AIM To investigate the effects of different goal caloric requirements of enteral nutrition on the gastrointestinal function and outcomes in the acute phase of sepsis.METHODS Patients were randomly assigned to receive 30%(defined as group A),60%(group B),or 100%(group C)of goal caloric requirements of enteral nutrition in this prospective pilot clinical trial.The acute gastrointestinal injury(AGI)grades,incidence of feeding intolerance(FI),daily caloric intake,nutritional and inflammatory markers,and biomarkers of mucosal barrier function were collected during the first 7 d of enteral feeding.The clinical severity and outcome variables were also recorded.RESULTS A total of 54 septic patients were enrolled.The days to goal calorie of group C(2.55±0.82)were significantly longer than those of group A(3.50±1.51;P=0.046)or B(4.85±1.68;P<0.001).The FI incidence of group C(16.5%)was higher than that of group A(5.0%)or B(8.7%)(P=0.009).No difference in the incidence of FI symptoms was found between groups A and B.The serum levels of barrier function biomarkers of group B were significantly lower than those of group A(P<0.05)on the 7th day of feeding.The prealbumin and IL-6 levels of group A were lower than those of group B(P<0.05)on the 7th day of feeding.No significant differences in the clinical outcome variables or 28-d mortality were found among the three groups.CONCLUSION Early moderate enteral underfeeding(60%of goal requirements)could improve the intestinal barrier function and nutritional and inflammatory status without increasing the incidence of FI symptoms in sepsis.However,further large-scale prospective clinical trials and animal studies are required to test our findings.Moreover,the effects of different protein intake on gastrointestinal function and outcomes should also be investigated in future work.

Research progress on the relationship between intestinal microecology and intestinal bowel disease

Intestinal microecology is the main component of human microecology.Intestinal microecology consists of intestinal microbiota,intestinal epithelial cells,and intestinal mucosal immune system.These components are interdependent and establish a complex interaction network that restricts each other.According to the impact on the human body,there are three categories of symbiotic bacteria,opportunistic pathogens,and pathogenic bacteria.The intestinal microecology participates in digestion and absorption,and material metabolism,and inhibits the growth of pathogenic microorganisms.It also acts as the body’s natural immune barrier,regulates the innate immunity of the intestine,controls the mucosal barrier function,and also participates in the intestinal epithelial cells’physiological activities such as hyperplasia or apoptosis.When the steady-state balance of the intestinal microecology is disturbed,the existing core intestinal microbiota network changes and leads to obesity,diabetes,and many other diseases,especially irritable bowel syndrome,inflammatory bowel disease(IBD),and colorectal malignancy.Intestinal diseases,including tumors,are particularly closely related to intestinal microecology.This article systematically discusses the research progress on the relationship between IBD and intestinal microecology from the pathogenesis,treatment methods of IBD,and the changes in intestinal microbiota.