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.

Olive oil ameliorate allergic response in ovalbumin-induced food allergy mouse by promoting intestinal mucosal immunity

The numerous health benefits of olive oil are widely known,however,it also provides anti-allergic properties that have not yet been fully defined.In this study,the anti-allergic activity of olive oil was evaluated by analyzing the clinical symptoms and immune-related factors in BALB/c mice that had ingested600 mg/(kg·day)olive oil for two weeks prior to the evaluation.An allergy model was subsequently constructed for analysis,the results of which showed that the olive oil reduced the scores of allergic symptoms in the mice,and up-regulated the hypothermia and the decline in the immune organ index.Moreover,fewer allergy-related cytokines and reduced intestinal inflammation was discovered in the olive oil-treated group.In addition,analysis of intestinal mucosal immune-related factors revealed that the olive oil promoted the expression of intestinal tight junction proteins(Claudin-1,Occludin,and ZO-1)and IL-22,and helped maintain the integrity of the intestinal epithelial physical barrier.Increased levels of mucin 2 andβ-defensin were also found in the intestinal mucus of the olive oil-treated mice.These findings suggest that the oral administration of olive oil effectively attenuated the ovalbumin-induced allergic immune response in the mice,and had a positive effect on intestinal epithelial mucosal immunity.

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.

Preventive effect of tetramethylpyrazine on intestinal mucosal injury in rats with acute necrotizing pancreatitis

AIM： To evaluate the role of microcirculatory disorder （MCD） and the therapeutic effectiveness ;of tetramethylpyrazine （TMP） on intestinal mucosa injury in rats with acute necrotizing pancreatitis （ANP）.METHODS： A total of 192 Sprague-Dawley rats were randomly divided into three groups： normal control group （C group）, ANP group not treated with TMP （P group）, ANP group treated with TMP （T group）. An ANP model was induced by injection of 50 g/L sodium taurocholate under the pancreatic membrane （4 mL/kg）. C group received isovolumetric injection of 9 g/L physiological saline solution using the same method. T group received injection of TMP （10 mL/kg） via portal vein. Radioactive biomicrosphere technique was used to measure the blood flow at 0.5, 2, 6 and 12 h after the induction of ANP. Samples of pancreas, distal ileum were collected to observe pathological changes using a validated histology score. Intestinal tissues were also used for examination of myeloperoxidase （MPO） expressed intraceUularly in azurophilic granules of neutrophils.RESULTS： The blood flow was significantly lower in P group than in C group （P 〈 0.01）. The pathological changes were aggravated significantly in P group. The longer the time, the severer the pathological changes. The intestinal MPO activities were significantly higher in P group than in C group （P 〈 0.01）. The blood flow of intestine was significantly higher in T group than in P group after 2 h （P 〈 0.01）. The pathological changes were alleviated significantly in T group. MPO activities were significantly lower in T group than in P group （P 〈 0.01 or P 〈 0.05）. There was a negative correlation between intestinal blood flow and MPO activity （r = -0.981, P 〈 0.01） as well as between intestinal blood flow and pathologic scores （r = -0.922, P 〈 0.05）.CONCLUSION： MCD is an important factor for intestinal injury in ANP. TMP can ameliorate the condition of MCD and the damage to pancreas and intestine.

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 clodronate-containing liposomes on intestinal mucosal injury in rats with severe acute pancreatitis

BACKGROUND: Severe acute pancreatitis (SAP) can result in intestinal mucosal injury. This study aimed to demonstrate the protective effect of clodronate-containing liposomes on intestinal mucosal injury in rats with SAP. METHODS: Liposomes containing clodronate or phosphate buffered saline (PBS) were prepared by the thin-film method SAP models were prepared by a uniform injection of sodium taurocholate (2 mL/kg body weight) into the subcapsular space of the pancreas. Sprague-Dawley rats were randomly divided into a control group (C group), a SAP plus PBS-containing liposomes group (P group) and a SAP plus clodronate-containing liposomes group (T group). At 2 and 6 hours after the establishment of SAP models, 2 mL blood samples were taken from the superior mesenteric vein to measure the contents of serum TNF-α and IL-12. Pathological changes in the intestine and pancreas were observed using hematoxylin and eosin staining, while apoptosis was detected using TUNEL staining. In addition, the macrophage markers cluster of differentiation 68 (CD68) in the intestinal tissue was assessed with immunohistochemistry. RESULTS: At the two time points, the levels of TNF-α and IL-12 in the P group were higher than those in the C group (P<0.05) Compared with the P group, the levels of TNF-α and IL-12 decreased in the T group (P<0.05). The pathological scores of the intestinal mucosa and pancreas in the T group were lower than those of the P group. In the T group, large numbers of TUNEL-positive cells were observed, but none or few in the C and P groups. The number of CD68-positive macrophages decreased in the T group.CONCLUSIONS: Clodronate-containing liposomes have prote- ctive effects against intestinal mucosal injury in rats with SAP. The blockade of macrophages may provide a novel therapeutic strategy in SAP.

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.

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.

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.

Effect of ecoimmunonutrition supports on maintenance of integrity of intestinal mucosal barrier in severe acute pancreatitis in dogs

Background One of the major causes of death in severe acute pancreatitis （SAP） is severe infection owing to bacterial translocation. Some clinical studies suggested that ecoimmunonutrition （EIN） as a new strategy had better treatment effect on SAP patients. But the experiment studies on the precise mechanism of the effect of EIN were less reported. In this study, we mainly investigated the effects of EIN on bacterial translocation in SAP model of dogs. Methods SAP was induced by retrograde infusion of 5% sodium taurocholate into the pancreatic duct in healthy hybrid dogs. The SAP dogs were supported with either parenteral nutrition （PN） or elemental enteral nutrition （EEN） or EIN. The levels of serum amylase, serum aminotransferase and plasma endotoxin were detected before and after pancreatitis induction. On the 7th day after nutrition supports, peritoneal fluid, mesenteric lymph nodes （MLN）, liver, and pancreas were collected for bacterial culture with standard techniques to observe the incidence of bacterial translocation. Pathology changes of pancreas were analyzed by histopathologic grading and scoring of the severity of pancreas, and the degree of intestinal mucosal damage was assessed by measuring mucosal thickness, villus height, and crypt depth of ileum. Results Compared with PN and EEN, EIN significantly decreased the levels of serum amylase, serum aminotransferase, plasma endotoxin, and the incidence of bacterial translocation. Furthermore, compared with the others, the histology scores of inflammation in pancreas and the ileum injury （ileum mocosa thickness, villus height, and crypt depth） were significantly alleviated by EIN （P〈0.05）. Moreover, concerning liver function, the serum levels of alanine aminotransferase, aspartate aminotransferase and albumin were ameliorating significantly in the EIN group. Conclusion Our results suggested that EIN could maintain the integrity of intestinal mucosal barrier and reducing the incidence of bacterial translocation in SAP dogs. Early EIN was safe and more effective treatment for SAP dogs.

Effect of Astragalus membranaceus injection on the activity of the intestinal mucosal mast cells after hemorrhagic shock-reperfusion in rats

Background The mechanism of mucosal damage induced by ischemia-reperfusion （IR） after hemorrhagic shock is complex; mast cells （MC） degranulation is associated with the mucosal damage. Astragalus membranaceus can protect intestinal mucosa against intestinal oxidative damage after hemorrhagic shock, and some antioxidant agents could prevent MC against degranulation. This study aimed to observe the effects of astragalus membranaceus injection on the activity of intestinal mucosal mast cells （IMMC） after hemorrhage shock-reperfusion in rats Methods Thirty-two Wistar rats were randomly divided into the normal group, model group, low dosage group, （treated with Astragalus membranacaus injection, 10 g crude medication/kg） and high dosage group （treated with Astragalus membranacaus injection, 20 g crude medication/kg）. The rat model of hemorrhagic shock-reperfusion was induced by hemorrhage for 60 minutes followed by 90 minutes of reperfusion. The animals were administrated with 3 ml of the test drug solution before reperfusion. At the end of study, intestinal pathology, ultrastructure of IMMC, and expression of tryptase were assayed. The levels of malondisldehyde （MDA）, TNF-α, histamine, and superoxide dismutase （SOD） activity in intestine were detected, and the number of IMMC was counted. Results The Chiu＇s score of the rats in the model group was higher than in other groups （P〈0.01）. The Chiu＇s score in the high dosage group was higher than that in the low dosage group （P〈0.05）. Hemorrhage-reperfusion induced IMMC degranulation： Astragalus membranaceus injection attenuated this degranulation. Expression of tryptase and the number of IMMC in the model group increased compared with the other groups （P〈0.01） and was significantly reduced by the treatments of Astragalus membranaceus injection at both doses. There was no significant difference between the two treatment groups （P〉0.05）. MDA content and concentration of TNF-α in the model group were higher than that in the other three groups （P〈0.05）, and the concentration of TNF-α in the low dosage group was higher than that in the high dosage group （P〈0.05）. SOD activity and the concentration of histamine in the model group were lower than the other three groups （P〈0.05）. There was a negative correlation between the Chiu＇s score and the concentration of histamine and a positive correlation between the Chiu＇s score and the concentration of TNF-α and between the SOD activity and the concentration of histamine in the four groups （P〈0.05）. Conclusion Astragalus membranaceus injection may reduce the damage to small intestine mucosa by inhibiting the activated IMMC after hemorrhagic shock.

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.

Effect of Weikang Capsule(胃康胶囊)on Aspirin-Related Gastric and Small Intestinal Mucosal Injury

Objective To investigate the effects of Weikang Capsule(胃康胶囊,WKC)on aspirin-related gastric and small intestinal mucosal injury by magnetically controlled capsule endoscopy(MCCE).Methods Patients taking enteric-coated aspirin aged 40-75 years were enrolled in Beijing Anzhen Hospital,Capital Medical University from January 2019 to December 2019.The patients continued taking aspirin Tablet(100 mg per day)and underwent MCCE before and after 1-month combined treatment with WKC(0.9 g per time orally,3 times per day).The gastrointestinal symptom score,gastric Lanza score,the duodenal,jejunal and ileal mucosal injury scores were used to evaluate the gastrointestinal injury before and after treatment.Adverse events including nausea,vomiting,abdominal pain,abdominal distension,abdominal discomfort,dizziness,or headache during MCCE and combined treatment were observed and recorded.Results Twenty-two patients(male/female,13/9)taking enteric-coated aspirin aged 59.5±11.3 years with a duration of aspirin use of 28.0(1.0,48.0)months were recruited.Compared with pre-treatment,the gastrointestinal symptom rating scale scores,gastric Lanza scores,and duodenal mucosal injury scores were significantly reduced after 1-month WKC treatment(P<0.05),and jejunal and ileal mucosal injury scores showed no obvious change.No adverse events occurred during the trial.Conclusions WKC can alleviate gastrointestinal symptoms,as well as gastric and duodenal mucosal injuries,in patients taking enteric-coated aspirin;it does not aggravate jejunal or ileal mucosal injury,which may be an effective alternative for these patients(Clinical trial registry No.ChiCTR1900025451).

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.