Intestinal Mucosal Barrier Function Research Articles

Mechanisms of Peitu Yimu acupuncture in repairing intestinal mucosal barrier by regulating CRF/CRFR1 pathway in diarrhea-predominant irritable bowel syndrome rats.

To investigate the effect of Peitu Yimu(strengthening spleen and soothing liver) acupuncture on intestinal mucosal barrier function and corticotropin-releasing factor (CRF)/CRF receptor 1 (CRFR1) pathway in rats with diarrhea-predominant irritable bowel syndrome (IBS-D), so as to explore its underlying mechanism in alleviating IBS-D. Forty female SD rats were randomly divided into blank, model, electroacupuncture (EA), and agonist groups, with 10 rats in each group. Except for the blank group, rats in the other groups were given folium sennae infusion by gavage combined with chronic unpredictable mild stress to establish IBS-D model. Rats in the EA group received acupuncture at "Tianshu"(ST25) and EA at "Zusanli"(ST36) and "Taichong"(LR3) (2 Hz/15 Hz) on one side for 20 min, with the side chosen alternately every other day, for 14 days after modeling. Rats in the agonist group received acupuncture 30 min after intravenous injection of CRFR1 agonist urocortin, with the same manipulation method and time as the EA group. Before and after intervention, visceral pain threshold and stool Bristol scores were measured. Elevated plus maze test and open field test were used to detect anxiety and depression like behavior of rats. ELISA was used to detect the contents of CRF and CRFR1 in rats serum. Immunohistochemistry was used to detect the positive expressions of CRF, CRFR1, zonula occludens protein 1(ZO-1), occlusal protein(Occludin), and closure protein 1 (Claudin-1) in colon tissue. Compared with the blank group, the visceral pain threshold, open arm time percentage (OT%), total distance of movement in the open field test, and positive expression of ZO-1, Occludin, and Claudin-1 in colon were decreased (P<0.01, P<0.05), while Bristol stool scores, serum CRF and CRFR1 contents, and positive expressions of CRF and CRFR1 in colon were increased (P<0.01) in the model group. After intervention and compared with the model group, the visceral pain threshold, OT%, total distance of movement in the open field test, and positive expressions of ZO-1, Occludin, and Claudin-1 in colon were increased (P<0.05, P<0.01), while Bristol stool scores, serum CRF and CRFR1 contents, and positive expressions of CRF and CRFR1 in colon were decreased (P<0.01) in the EA group；the Bristol stool scores, serum CRF content, and CRF positive expression in colon were significantly decreased in the agonist group (P<0.01). Peitu Yimu acupuncture can significantly improve visceral hypersensitivity and anxiety-depression state in IBS-D rats. Its mechanism may be related to the inhibition of CRF/CRFR1 pathway and restoration of intestinal tight junction protein expressions.

Berberine mitigates diclofenac-induced intestinal mucosal mechanical barrier dysfunction through the restoration of autophagy by inhibiting exosome-mediated lncRNA H19.

Small intestine damage caused by diclofenac is called diclofenac enteropathy. Berberine (BBR), a class of isoquinoline alkaloids derived from Berberis vulgaris and Phellodendron amurense, is widely used in intestinal diseases. The present study evaluated the protective effect of BBR on the intestinal mucosal mechanical barrier in diclofenac enteropathy and its possible action mechanism. The in vitro animal experiment revealed that BBR downregulated the expression of long non-coding RNA H19 (lncRNA H19) in the small intestine and exosomes. In the co-culture experiment involving exosomes and intestinal epithelial cell-6(IEC-6) cells, the results of qRT-PCR, western blotting, and immunofluorescence assays demonstrated that the elevated expression of lncRNA H19 in the small intestine, conveyed via exosomes derived from the diclofenac group, suppressed the expression levels of autophagy-associated protein 5 (Atg 5) and light chain 3 (LC 3), as well as and the tight junction (TJ) proteins zonula occludens-1 (ZO-1), claudin-1, and occluding, relative to the control group. BBR treatment attenuated exosomal lncRNA H19 levels, upregulated the expression of Atg5 and LC3 expression, enhanced TJ protein expression, and increased the light chain 3 (LC3)-II/LC3-I ratio. These findings significantly elucidated that BBR promoted the restoration of autophagy in IECs by inhibiting exosomal lncRNA H19, thereby mitigating the impairment of the intestinal mucosal mechanical barrier function in diclofenac enteropathy. The process involving exosomal lncRNA H19 regulating autophagy, thereby affecting the intestinal mucosal mechanical barrier, offers a novel perspective for the application of BBR in the treatment of diclofenac enteropathy.

Heat-killed Akkermansia muciniphila ameliorates allergic airway inflammation in mice

Allergic asthma (AA) is a common inflammatory airway disease characterized by increased airway hyper-responsiveness (AHR), inflammation, and remodeling. Akkermansia muciniphila is a strictly anaerobic bacterium residing in the gut and is a promising next-generation probiotic to improve metabolic inflammatory syndrome. A recent study suggested the beneficial effect of live A. muciniphila on allergic airway inflammation (AAI) in mice. However, whether the heat-killed form can improve AAI requires further investigation. Mice sensitized and challenged with house dust mites (HDM) develop AA hallmarks including inflammatory cell infiltration, goblet cell hyperplasia, and subepithelial collagen deposition in the lungs. These phenomena were reversed by oral administration of the heat-killed A. muciniphila strain EB-AMDK19 (AMDK19-HK) isolated from the feces of healthy Koreans. Furthermore, AMDK19-HK diminished the HDM-induced AHR to inhaled methacholine, lung mast cell accumulation, and serum HDM-specific IgE levels. It also led to the overall suppression of IL-4, IL-13, and eotaxin production in bronchoalveolar lavage fluids, and Il4, Il5, Il13, and Ccl17 gene expression in lung tissues. Moreover, AMDK19-HK suppressed Th2-associated cytokine production in the splenocytes of HDM-sensitized mice in vitro. Additionally, a combination of 16S rRNA gene sequencing and short-chain fatty acid (SCFA) analysis in cecal samples revealed that AMDK19-HK modulated the relative abundance of circulating SCFA-associated gut genera, including a positive correlation with Lachnospiraceae_ NK4A136_group and a negative correlation with Lachnoclostridium and significantly increased cecal SCFA concentrations. Finally, AMDK19-HK improved intestinal mucosal barrier function. These results suggest that the oral administration of AMDK19-HK ameliorates HDM-induced AAI in mice by suppressing Th2-mediated immune responses and could have a protective effect against AA development.

Role of Vitamin D in the Pathogenesis of Inflammatory Bowel Diseases: Literature Review

The pathogenesis of inflammatory bowel diseases still remains unclear nowadays. Genetic disposition, impaired immune regulation, disturbance in intestinal microbiota composition, exposure to environmental factors are associated with the development of inflammation in intestinal mucosa and increased epithelial penetrance that define disease's development and progression. There is a theory in scientific literature that vitamin D deficiency (among other environmental factors) increases the risk of inflammatory bowel disease. However, the role of vitamin D in the development of gastrointestinal tract diseases remains poorly studied. This article presents current data on the vitamin D effect on the intestinal mucosa barrier function, on the immune system and on the intestinal microbiota in the context of inflammatory bowel diseases pathogenesis.

Regulation of Mouse Digestive Function, Intestinal Mucosal Barrier Function, and Inflammatory Reaction by Lycium Barbarum Polysaccharide Pathway through Myosin Light Chain Kinase

This research investigated the impacts of lycium barbarum polysaccharide (LBP) on the digestive function, intestinal mucosal barrier function, inflammatory response, and myosin light chain kinase (MLCK) signaling pathway in immunosuppressed mice. 70 mg/kg cyclophosphamide was injected into abdomen for the preparation of immune suppression model. Healthy BALB/c mice served as control for the analysis of the differences in gastrointestinal motility and absorptive capacity, intestinal mucosal barrier function, the phagocytic ability of abdominal macrophages, serum immune factor and inflammatory factor levels, and the activation status of the MLCK signaling pathway after continuous gavage with 100 mg/kg LBP. Results revealed a decrease in D-xylose content, phagocytic rate, index of abdominal macrophages, and spleen index in the serum and urine of model mice compared to those of controls. In addition, levels of IgA, IgG, IgM, IL-6 (interleukin-6), IL-12, and interferon-γ (IFN-γ) decreased, while MLCK and myosin light chain (MLC) levels rose (P<0.01). Versus those in Model group, urine D-xylose content, phagocytic rate, index of abdominal macrophages, spleen index, and the levels of IgA, IgG, IgM, IL-6, IL-12, and IFN-γ of mice undergoing the gavage with LBP increased, while MLCK and p-MLC levels declined (P<0.05). In conclusion, LBP improved digestive absorption and immune function of immunosuppressed mice and regulated intestinal mucosal barrier immune system by inhibiting MLCK signaling pathway activation.

Therapeutic Implications of Phenolic Acids for Ameliorating Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD) is a chronic inflammatory intestinal disorder, and its complex etiology makes prevention and treatment challenging. Research on new drugs and treatment strategies is currently a focal point. Phenolic acids are widely present in plant-based diets and have demonstrated the potential to alleviate colitis due to their powerful antioxidant and anti-inflammatory properties. In this review, we provide an overview of the structures and main dietary sources of phenolic acids, encompassing benzoic acid and cinnamic acid. Additionally, we explore the potential of phenolic acids as a nutritional therapy for preventing and treating IBD. In animal and cell experiments, phenolic acids effectively alleviate IBD induced by drug exposure or genetic defects. The mechanisms include improving intestinal mucosal barrier function, reducing oxidative stress, inhibiting excessive activation of the immune response, and regulating the balance of the intestinal microbiota. Our observation points towards the need for additional basic and clinical investigations on phenolic acids and their derivatives as potential novel therapeutic agents for IBD.

Pure total flavonoids from Citrus ameliorate NSAIDs-induced intestinal mucosal injury via regulation of exosomal LncRNA H19 and protective autophagy

IntroductionNon-steroid anti-inflammatory drugs (NSAIDs) are a class of prescription drugs with antipyretic, analgesic, anti-inflammatory, and antiplatelet effects. However, long-term use of NSAIDs will disrupt the intestinal mucosal barrier, causing erosion, ulcers, bleeding, and even perforation. Pure total flavonoids from Citrus (PTFC) is extracted from the dried peel of Citrus, showing a protective effect on intestinal mucosal barrier with unclear mechanisms. MethodsIn the present study, we used diclofenac (7.5 mg kg−1, i.g.) to induce a rat model of NSAIDs-related intestinal lesions. PTFC (50, 75, 100 mg·kg−1 d−1, i.g.) was administered 9 days before the initial diclofenac administration, followed by co-administration on the last 5 days. Exosomes were identified by western blotting and transmission electron microscopy (TEM), and then co-cultured with IEC-6 cells. The expression of long non-coding RNA (lncRNA) H19, autophagy-related 5 (Atg5), ZO-1, Occludin, and Claudin-1 were detected by quantitative real-time PCR (qRT-PCR). The expression of light chain 3 (LC3)-I, LC3-II, ZO-1, Occludin and Claudin-1 proteins was tested by western blotting. The localization of both exosomes and autophagosomes was examined by immunofluorescent technique. ResultsThe treatment of PTFC attenuated intestinal mucosal mechanical barrier function disturbance in diclofenac-induced NSAIDs rats. IEC-6 cells co-cultured with NSAIDs rats-derived exosomes possessed the lowest levels of protective autophagy, and severe intestinal barrier injuries. Cells co-cultured with the exosomes extracted from rats administrated PTFC exhibited an improvement of autophagy and intestinal mucosal mechanical barrier function. The prevention effect was proportional to the concentration of PTFC administered. ConclusionPTFC ameliorated NSAIDs-induced intestinal mucosal injury by down-regulating exosomal lncRNA H19 and promoting autophagy.

CircSOD2: Disruption of intestinal mucosal barrier function in ulcerative colitis by regulating the miR-378g/Snail1 axis.

Circular RNA (circRNA) has been found to mediate ulcerative colitis (UC) progression by regulating intestinal mucosal barrier function. However, the role of circSOD2 in UC process and its underlying molecular mechanism still need to be further elucidated. Lipopolysaccharide (LPS)-induced Caco2 cells were used to mimic UC cell models. CircSOD2, miR-378g, and Snail1 levels were determined by quantitative real-time PCR. Cell viability was detected using MTT assay, and inflammatory cytokine levels were measured using ELISA. The intestinal mucosal barrier function was evaluated by testing transepithelial electrical resistance and fluorescein isothiocyanate (FITC)-dextran permeability. Snail1 and tight junction-related markers (Zo-1 and Claudin2) protein levels were examined using western blot. The interaction between miR-378g and circSOD2 or Snail1 was confirmed by dual-luciferase reporter assay. Dextran sulfate sodium (DSS) was used to induce UC rat models in vivo. CircSOD2 was overexpressed in UC patients, and its knockdown significantly increased cell viability, transepithelial electrical resistance, and tight junction-related protein expression, while reduced inflammation cytokine levels and the permeability of FITC-dextran in LPS-induced Caco2 cells. In terms of mechanism, circSOD2 sponged miR-378g to positively regulate Snail1 expression. MiR-378g inhibitor reversed the effect of circSOD2 knockdown on intestinal mucosal barrier injury and Snail1 expression in LPS-induced Caco2 cells. In DSS-induced UC rat models, circSOD2 knockdown also could repair the intestinal mucosal barrier injury through regulating miR-378g/Snail1 axis. CircSOD2 could destroy intestinal mucosal barrier function in LPS-induced Caco2 cells and DSS-induced UC rats by miR-378g/Snail1 axis.

Short-chain fatty acid-producing bacterial strains attenuate experimental ulcerative colitis by promoting M2 macrophage polarization via JAK/STAT3/FOXO3 axis inactivation

BackgroundPatients with inflammatory bowel disease (IBD), dysbiosis, and immunosuppression who receive fecal microbiota transplantation (FMT) from healthy donors are at an increased risk of developing bacteremia. This study investigates the efficacy of a mixture of seven short-chain fatty acid (SCFA)-producing bacterial strains (7-mix), the resulting culture supernatant mixture (mix-sup), and FMT for treating experimental ulcerative colitis (UC) and evaluates underlying mechanisms.MethodsUtilizing culturomics, we isolated and cultured SCFA-producing bacteria from the stool of healthy donors. We used a mouse model of acute UC induced by dextran sulfate sodium (DSS) to assess the effects of 7-mix, mix-sup, and FMT on intestinal inflammation and barrier function, microbial abundance and diversity, and gut macrophage polarization by flow cytometry, immunohistochemistry, 16S rRNA gene sequencing, and transwell assays.ResultsThe abundance of several SCFA-producing bacterial taxa decreased in patients with UC. Seven-mix and mix-sup suppressed the inflammatory response and enhanced intestinal mucosal barrier function in the mouse model of UC to an extent similar to or superior to that of FMT. Moreover, 7-mix and mix-sup increased the abundance of SCFA-producing bacteria and SCFA concentrations in colitic mice. The effects of these interventions on the inflammatory response and gut barrier function were mediated by JAK/STAT3/FOXO3 axis inactivation in macrophages by inducing M2 macrophage polarization in vivo and in vitro.ConclusionsOur approach provides new opportunities to rationally harness live gut probiotic strains and metabolites to reduce intestinal inflammation, restore gut microbial composition, and expedite the development of safe and effective treatments for IBD.

Octreotide attenuates intestinal barrier damage by maintaining basal autophagy in Caco2 cells.

The intestinal mucosal barrier is of great importance for maintaining the stability of the internal environment, which is closely related to the occurrence and development of intestinal inflammation. Octreotide (OCT) has potential applicable clinical value for treating intestinal injury according to previous studies, but the underlying molecular mechanisms have remained elusive. This article is based on a cell model of inflammation induced by lipopolysaccharide (LPS), aiming to explore the effects of OCT in protecting intestinal mucosal barrier function. A Cell Counting Kit‑8 assay was used to determine cell viability and evaluate the effectiveness of OCT. Gene silencing technology was used to reveal the mediated effect of somatostatin receptor 2 (SSTR2). The changes in intestinal permeability were detected through trans‑epithelial electrical resistance and fluorescein isothiocyanate‑dextran 4 experiments, and the alterations in tight junction proteins were detected using immunoblotting and reverse transcription fluorescence‑quantitative PCR technology. Autophagosomes were observed by electron microscopy and the dynamic changes of the autophagy process were characterized by light chain (LC)3‑II/LC3‑I conversion and autophagic flow. The results indicated that SSTR2‑dependent OCT can prevent the decrease in cell activity. After LPS treatment, the permeability of monolayer cells decreased and intercellular tight junctions were disrupted, resulting in a decrease in tight junction protein zona occludens 1 in cells. The level of autophagy‑related protein LC3 was altered to varying degrees at different times. These abnormal changes gradually returned to normal levels after the combined application of LPS and SSTR2‑dependent OCT, confirming the role of OCT in protecting intestinal barrier function. These experimental results suggest that OCT maintains basal autophagy and cell activity mediated by SSTR2 in intestinal epithelial cells, thereby preventing the intestinal barrier dysfunction in inflammation injury.

Serum Zonulin as a Marker of Intestinal Mucosal Barrier Function in Chronic Liver Diseases in Pediatrics

Serum Zonulin as a Marker of Intestinal Mucosal Barrier Function in Chronic Liver Diseases in Pediatrics

Studies Related to the Involvement of EsA in Improving Intestinal Inflammation in Acute Pancreatitis via the NF-κB Pathway.

Acute pancreatitis (AP) is a clinically frequent acute abdominal condition, which refers to an inflammatory response syndrome of edema, bleeding, and even necrosis caused by abnormal activation of the pancreas's own digestive enzymes. Intestinal damage can occur early in the course of AP and is manifested by impaired intestinal mucosal barrier function, and inflammatory reactions of the intestinal mucosa, among other factors. It can cause translocation of intestinal bacteria and endotoxins, further aggravating the condition of AP. Therefore, actively protecting the intestinal mucosal barrier, controlling the progression of intestinal inflammation, and improving intestinal dynamics in the early stages of AP play an important role in enhancing the prognosis of AP. The viability and apoptosis of RAW264.7 cells treated with Esculentoside A (EsA) and/or lipopolysaccharide were detected using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry, respectively. The expression of apoptosis-related proteins and NF-κB signaling pathway-related proteins were detected by western blot (WB). An enzyme-linked immunosorbent assay was used to measure TNF-α and IL-6 secretion. In vitro experiments demonstrated that EsA not only promoted the apoptosis of inflammatory cells but also reduced the secretion of TNF-α and IL-6 in a dose-dependent manner. Additionally, it inhibited the activation of the NF-κB signaling pathway by decreasing the expression of phosphorylated-p65(p-p65) and elevating the expression of IκBα. Similarly, in vivo experiments using a rat AP model showed that EsA inhibited the expression of p-p65 elevating the expression of IκBα in the intestinal tissues of the rat AP model and promoting the apoptosis of inflammatory cells in the intestinal mucosa in vivo experiments, while improving the pathological outcome of the pancreatic and intestinal tissues. Our results suggest that EsA can reduce intestinal inflammation in the rat AP model and that EsA may be a candidate for treating intestinal inflammation in AP and further arresting AP progression.

Intestinal melatonin levels and gut microbiota homeostasis are independent of the pineal gland in pigs.

Melatonin (MEL) is a crucial neuroendocrine hormone primarily produced by the pineal gland. Pinealectomy (PINX) has been performed on an endogenous MEL deficiency model to investigate the functions of pineal MEL and its relationship with various diseases. However, the effect of PINX on the gastrointestinal tract (GIT) MEL levels and gut microbiome in pigs has not been previously reported. By using a newly established pig PINX model, we detected the levels of MEL in the GIT by liquid chromatography-tandem mass spectrometry. In addition, we examined the effects of PINX on the expression of MEL synthesis enzymes, intestinal histomorphology, and the intestinal barrier. Furthermore, 16S rRNA sequencing was performed to analyze the colonic microbiome. PINX reduced serum MEL levels but did not affect GIT MEL levels. Conversely, MEL supplementation increased MEL levels in the GIT and intestinal contents. Neither PINX nor MEL supplementation had any effect on weight gain, organ coefficient, serum biochemical indexes, or MEL synthetase arylalkylamine N-acetyltransferase (AANAT) expression in the duodenum, ileum, and colon. Furthermore, no significant differences were observed in the intestinal morphology or intestinal mucosal barrier function due to the treatments. Additionally, 16S rRNA sequencing revealed that PINX had no significant impact on the composition of the intestinal microbiota. Nevertheless, MEL supplementation decreased the abundance of Fibrobacterota and increased the abundance of Actinobacteriota, Desulfobacterota, and Chloroflexi. We demonstrated that synthesis of MEL in the GIT is independent of the pineal gland. PINX had no influence on intestinal MEL level and microbiota composition in pigs, while exogenous MEL alters the structure of the gut microbiota.

A Novel Lactobacillus brevis Fermented with a Vegetable Substrate (AL0035) Counteracts TNBS-Induced Colitis by Modulating the Gut Microbiota Composition and Intestinal Barrier.

Crohn's and ulcerative colitis are common conditions associated with inflammatory bowel disease as well as intestinal flora and epithelial barrier dysfunction. A novel fermented Lactobacillus brevis (AL0035) herein assayed in a trinitro benzene sulfonic acid (TNBS)-induced colitis mice model after oral administration significantly counteracted the body weight loss and improves the disease activity index and histological injury scores. AL0035 significantly decreased the mRNA and protein expression of different pro-inflammatory cytokines (TNFalpha, IL-1beta, IL-6, IL-12, IFN-gamma) and enhanced the expression of IL-10. In addition, the probiotic promoted the expression of tight junction proteins, such as ZO-1, keeping the intestinal mucosal barrier function to attenuate colitis symptoms in mice. Markers of inflammation cascade such as myeloperoxidase (MPO) and PPAR-gamma measured in the colon were also modified by AL0035 treatment. AL0035 was also able to reduce different lymphocyte markers' infiltration in the colon (GATA-3, T-Bet, NK1.1) and monocyte chemoattractant protein-1 (MCP-1/CCL2), a key chemokine involved in the migration and infiltration of monocytes/macrophages in the immunological surveillance of tissues and inflammation. In colonic microbiota profile analysis through 16S rRNA sequencing, AL0035 increased the microbial diversity depleted by TNBS administration and the relative abundance of the Lactobacillaceae and Lachnospiraceae families, whereas it decreased the abundance of Proteobacteria. Altogether, these data indicated that AL0035 could lower the severity of colitis induced by TNBS by regulating inflammatory cytokines, increasing the expression of tight junction proteins and modulating intestinal microbiota, thus preventing tissue damage induced by colitis.

Polygonatum sibiricum Saponin Prevents Immune Dysfunction and Strengthens Intestinal Mucosal Barrier Function in Cyclophosphamide-Induced Immunosuppressed BALB/c Mice.

The aim of this study was to explore the immunomodulatory effect of Polygonatum sibiricum saponin (PS) in a cyclophosphamide-induced (Cy) immunosuppression mice model. Oral administration of PS by gavage effectively alleviated weight loss caused by Cy and increased the index of immune organs. PS promoted the proliferation of splenic lymphocytes and T cell subsets (CD3+, CD355+, CD4+/CD8+) and relieved the xylene-induced inflammatory response and Cy-induced increase of serum hemolysin. Moreover, PS increased serum levels of lactate dehydrogenase and acid phosphatase. PS elevated serum level of cytokines and immunoglobulins (TNF-α, IFN-γ, IL-4, IL-6, IL-β, SIgA, and IgG) and the expression of mRNA of IL-10, TNF-α, and IL-6 in the spleen. Increased mRNA expression of tight junction protein (ZO-1, Mucin2, Occludin) expression and protein expression of IL-6/MyD88/TLR4 in the small intestine showed that PS exhibited a restorative effect on intestinal mucosal injury caused by cyclophosphamide. Oral PS prevented Cy-induced decline in leukocytes, red blood cells, lymphocytes, hemoglobin concentrations, and neutrophils, providing evidence for alleviating hematopoietic disorders. In addition, PS increased SOD and NO levels, reduced MDA levels, and improved oxidative damage in the liver. These findings demonstrate that PS has the potential to be developed as a supplemental agent for alleviating immunosuppression caused by chemotherapeutic agents.

Bacillus amyloliquefaciens SC06 Relieving Intestinal Inflammation by Modulating Intestinal Stem Cells Proliferation and Differentiation via AhR/STAT3 Pathway in LPS-Challenged Piglets.

Bacillus amyloliquefaciens is a well-accepted probiotic, with many benefits for both humans and animals. The ability of intestinal stem cells (ISCs) to develop into several intestinal epithelial cell types helps accelerate intestinal epithelial regeneration. Limited knowledge exists on how bacteria regulated ISCs proliferation and regeneration. Our study investigated the effects of Bacillus amyloliquefaciens supplementation on ISC proliferation and regeneration and intestinal mucosal barrier functions in piglets exposed to lipopolysaccharide (LPS). Eighteen piglets (male, 21 days old) were randomly split into 3 clusters: CON cluster, LPS cluster, and SC06+LPS cluster. On day 21, 100 μg/kg body weight of LPS was intraperitoneally administered to the SC06+LPS and LPS groups. We found SC06 supplementation maintained the intestinal barrier integrity, enhanced intestinal antioxidant capacity, reduced generation of inflammatory response, and suppressed enterocyte apoptosis against the deleterious effects triggered by LPS. In addition, our research indicated that the SC06 supplementation not only improved the ISC regeneration, but also resulted in upregulation of aryl hydrocarbon receptor (AhR) in LPS-challenge piglets. Further studies showed that SC06 also induced ISC differentiation toward goblet cells and inhibited their differentiation to intestinal absorptive cells and enterocytes. The coculture system of SC06 and ileum organoids revealed that SC06 increased the growth of ISCs and repaired LPS-induced organoid damage through activating the AhR/STAT3 signaling pathway. These findings showed that SC06, possibly through the AhR/STAT3 pathway, accelerated ISC proliferation and promoted epithelial barrier healing, providing a potential clinical treatment for IBD. Our research demonstrated that SC06 is effective in preventing intestinal epithelial damage after pathological injury, restoring intestinal homeostasis, and maintaining intestinal epithelial regeneration.

Fermented Corn-Soybean Meal Improved Growth Performance and Reduced Diarrhea Incidence by Modulating Intestinal Barrier Function and Gut Microbiota in Weaned Piglets.

This study aimed to investigate the effects of fermented corn-soybean meal mixed feed (FMF) on growth performance, intestinal barrier function, gut microbiota and short-chain fatty acids in weaned piglets. A total of 128 weaned piglets [Duroc×(Landrace×Yorkshire), male, 21-day-old] were randomly allocated to four groups. Piglets were fed a control diet (CON) or the control diet supplemented with 10%, 50% or 100% FMF (FMF-10, FMF-50 or FMF-100, respectively) for 14 d. The results showed that the FMF-100 group had higher average daily gain and average daily feed intake and lower diarrhea incidence than the CON group (p < 0.05). The FMF-50 and FMF-100 groups had greater villus height in the duodenum and jejunum, and the FMF-10 and FMF-100 groups had higher villus height-to-crypt depth ratio in the duodenum and jejunum than the CON group. Additionally, the FMF-100 group had higher protein expression of duodenal, jejunal and ileal ZO-1 and jejunal claudin-1; higher mRNA expression of duodenal and ileal TJP1 and jejunal CLDN1 and IL10; and lower jejunal IL1B mRNA expression (p < 0.05). The FMF-50 group showed higher jejunal ZO-1 and claudin-1 protein levels, higher mRNA expression levels of IL10 and TJP1 and lower levels of TNF in the jejunum; the FMF-10 group had higher mRNA expression levels of IL10 and lower levels of TNF in the jejunum than the CON group (p < 0.05). Furthermore, the FMF-10 and FMF-50 groups had higher colonic Lactobacillus abundance and butyrate levels; the FMF-100 group had higher abundance of colonic butyrate, Lactobacillus and Faecalibacterium than the CON group (p < 0.05). Collectively, our results suggest that FMF could improve intestinal mucosal barrier function, gut microbiota and their metabolites, thereby enhancing average daily gain and reducing diarrhea incidence in weaned piglets.

Effects of dietary astaxanthin supplementation on growth performance, antioxidant status, immune response, and intestinal health of rainbow trout (Oncorhynchus mykiss)

A feeding trial was conducted to assess the impacts of dietary astaxanthin from wall-broken Haematococcus pluvialis (WBHPA) on the growth performance, antioxidant status, immune response, and intestinal health of rainbow trout (Oncorhynchus mykiss). Six experimental diets were formulated with various concentrations of WBHPA, ranging from 0 to 8.4 g/kg (containing 0 to 125 mg/kg astaxanthin). Each diet was fed to triplicate groups of rainbow trout (mean initial weight of 561 g) twice daily for 9 consecutive weeks. The survival rate and feed intake of fish exhibited no significant differences among the dietary groups (P > 0.05). Similarly, dietary inclusion of 25 to 100 mg/kg astaxanthin did not significantly affect the weight gain and daily growth coefficient (P > 0.05), but excessive inclusion of astaxanthin (125 mg/kg) slightly depressed these parameters (P < 0.05). Dietary inclusion of 25 to 50 mg/kg astaxanthin increased the activities of intestinal digestion and absorption enzymes (lipase, creatine kinase, and alkaline phosphatase), while the inclusion of 25 to 75 mg/kg astaxanthin improved the immune response of fish. Furthermore, regardless of inclusion level (25 to 125 mg/kg), dietary astaxanthin supplementation strengthened the intestinal mucosal barrier function and improved antioxidant activity, thereby promoting intestinal development. Conclusively, 25 to 75 mg/kg astaxanthin from WBHPA was recommended to be included in diets for rainbow trout.

Research progress on the mechanism of probiotics regulating cow milk allergy in early childhood and its application in hypoallergenic infant formula.

Some infants and young children suffer from cow's milk allergy (CMA), and have always mainly used hypoallergenic infant formula as a substitute for breast milk, but some of these formulas can still cause allergic reactions. In recent years, it has been found that probiotic nutritional interventions can regulate CMA in children. Scientific and reasonable application of probiotics to hypoallergenic infant formula is the key research direction in the future. This paper discusses the mechanism and clinical symptoms of CMA in children. This review critically ex- amines the issue of how probiotics use intestinal flora as the main vector to combine with the immune system to exert physiological functions to intervene CMA in children, with a particular focus on four mechanisms: promoting the early establishment of intestinal microecological balance, regulating the body's immunity and alleviating allergic response, enhancing the intestinal mucosal barrier function, and destroying allergen epitopes. Additionally, it overviews the development process of hypoallergenic infant formula and the research progress of probiotics in hypoallergenic infant formula. The article also offers suggestions and outlines potential future research directions and ideas in this field.

Tannic acid alleviates ETEC K88-induced intestinal damage through regulating the p62-keap1-Nrf2 and TLR4-NF-κB-NLRP3 pathway in IPEC-J2 cells.

Tannic acid (TA), a naturally occurring polyphenol, has shown diverse potential in preventing intestinal damage in piglet diarrhea induced by ETEC K88. However, the protective effect of TA on ETEC k88 infection-induced post-weaning diarrhea and its potential mechanism has not been well elucidated. Therefore, an animal trial was carried out to investigate the effects of dietary supplementation with TA on the intestinal diarrhea of weaned piglets challenged with ETEC K88. In addition, porcine intestinal epithelial cells were used as an in vitro model to explore the mechanism through which TA alleviates intestinal oxidative damage and inflammation. The results indicated that TA supplementation (2 g·kg-1 and 4 g·kg-1 ) reduced diarrhea rate, enzyme activity (DAO and MAD) and serum inflammatory cytokines concentration (TNF-α, IL-1β) (P < 0.05) compared to the IG group in vivo. In vitro, TA treatment effectively alleviated ETEC-induced cytotoxicity, increased the expression of ZO-1, occludin and claudin-1 at both mRNA and protein levels. Moreover, TA pre-treatment increased the activity of antioxidant enzymes (such as T-SOD) and decreased serum cytokine levels (TNF-α, IL-1β). Furthermore, TA increased cellular antioxidant capacity by activating the Nrf2 signaling pathway and decreased inflammatory response by down-regulating the expression of TLR4, MyD88, NF-kB and NLRP3. The study showed that TA reduced the diarrhea rate of weaned piglets by restoring the intestinal mucosal mechanical barrier function, alleviating oxidative stress and inflammation. The underlying mechanismwas achieved by modulating p62-keap1-Nrf2 and TLR4-NF-κB-NLRP3 pathway. This article is protected by copyright. All rights reserved.