Animal Models Of Colitis Research Articles

Dextran sodium sulfate potentiates NLRP3 inflammasome activation by modulating the KCa3.1 potassium channel in a mouse model of colitis.

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, has increased in incidence and prevalence in recent decades. Both clinical and animal studies are critical for understanding the pathogenesis of this disease. Dextran sodium sulfate (DSS)-induced colitis is a frequently used animal model of IBD, but the underlying mechanism of the model remains incompletely understood. In this study, we found that NOD-like receptor family pyrin containing 3 (NLRP3) depletion markedly mitigated DSS-induced colitis and was accompanied by decreased activation of the inflammasome in the colons of mice. However, in vitro assays showed that DSS did not directly trigger but instead potentiated NLRP3 inflammasome assembly in macrophages in response to suboptimal ATP or nigericin stimulation. Mechanistically, DSS potentiated NLRP3 inflammasome activation in macrophages by augmenting KCa3.1-mediated potassium ion (K+) efflux. Furthermore, we found that pharmacologic blockade of the K+ channel KCa3.1 with TRAM-34 or genetic depletion of the Kcnn4 gene (encoding KCa3.1) not only ameliorated the severity of DSS-induced colitis but also attenuated in vivo inflammasome assembly in the colonic tissues of mice, suggesting a causal link between KCa3.1-mediated augmentation of the NLRP3 inflammasome and DSS-induced inflammatory injuries. Collectively, these results indicate that KCa3.1 plays a critical role in mediating DSS-induced colitis in mice by potentiating NLRP3 inflammasome activation. Our data provide a previously unknown mechanism by which DSS induces colitis in mice and suggests that KCa3.1 is an alternative therapeutic target for treating IBD.

PDIA2 Bridges Endoplasmic Reticulum Stress and Metabolic Reprogramming During Malignant Transformation of Chronic Colitis.

BackgroundChronic inflammation contributes to approximately 20% of cancers; the underlying mechanisms are still elusive. Here, using an animal model of colitis to colon-cancerous transformation, we demonstrated that endoplasmic reticulum (ER) stress couples with metabolic reprogramming to promote a malignant transformation of chronic inflammation.MethodsThe animal model for chronic colitis to colon-cancerous transformation was established in C57BL/6N mice by azoxymethane (AOM) and dextran sodium sulfate (DSS) treatments. The differential proteins in control and AOM/DSS-treated colon mucosa were determined using proteomic analysis; the kinetics of metabolic modifications were monitored by mitochondrial oxygen flux, extracellular acidification, and targeted metabolomics; the molecule linker between ER stress and metabolic modifications were identified by coimmunoprecipitation, KEGG pathway analysis, and the subcutaneous tumor model using gene-specific knockdown colon cancer cells. Tissue array analysis were used to evaluate the differential protein in cancer and cancer-adjacent tissues.ResultsAOM/DSS treatment induced 38 tumors in 10 mice at the 14th week with the mean tumor size 9.35 ± 3.87 mm2, which was significantly decreased to 5.85 ± 0.95 mm2 by the ER stress inhibitor 4-phenylbutyric acid (4PBA). Seven differential proteins were determined from control (1,067 ± 48) and AOM/DSS-treated mucosa (1,077 ± 59); the level of ER protein PDIA2 (protein disulfide isomerase-associated 2) was increased over 7-fold in response to AOM/DSS treatment. PDIA2 interacted with 420 proteins that were involved in 8 signaling pathways, in particular with 53 proteins in metabolic pathways. PDIA2 translocated from ER to mitochondria and interacted with the components of complexes I and II to inhibit oxophosphorylation but increase glycolysis. Knockdown PDIA2 in colon cancer cells restored the metabolic imbalance and significantly repressed tumor growth in the xenograft animal model. 4PBA therapy inhibited the AOM/DSS-mediated overexpression of PDIA2 and metabolic modifications and suppressed colon cancer growth. In clinic, PDIA2 was overexpressed in colon cancer tissues rather than cancer-adjacent tissues and was related with the late stages and lymph node metastasis of colon cancer.ConclusionsPersistent ER stress reprograms the metabolism to promote the malignant transformation of chronic colitis; PDIA2 serves as a molecule linker between ER stress and metabolic reprogramming. The inhibition of ER stress restores metabolic homeostasis and attenuates the cancerous transformation of chronic inflammation.

Effects of Prebiotic Fructooligosaccharides on Susceptibility to Dextran Sodium Sulfate‐Induced Colitis

Inflammatory bowel disease (IBD) is a chronic intestinal disease that includes Crohn’s disease and ulcerative colitis. Previous studies have found alterations in the microbiome in IBD and in animal models of IBD, underscoring the role of the intestinal microbiota in IBD pathogenesis. Prebiotics are molecules in foods, such as fructooligosaccharides and other soluble fiber molecules, that support the growth or activity of beneficial probiotic microbes. Previous studies suggest that prebiotics can reduce symptoms in models of colitis. This study aimed to determine whether pretreatment with 1% short‐chain fructooligosacchardies (FOS) for 1 week, followed by 8 days of 3% DSS administration with continued FOS treatment, altered the severity of disease in C57Bl/6 mice. Clinical signs of colitis, including weight loss, fecal occult blood, and fecal consistency, were monitored daily during the DSS treatment period and the daily disease activity index was calculated. At the end of the experiment, samples were collected for histological scoring, and for RNA isolation and analysis of colonic pro‐inflammatory cytokine expression by RT‐PCR. Through the 8 days of DSS treatment, the disease activity index increased in both DSS‐treated and FOS/DSS‐treated mice compared to control non‐colitic mice, but was not significantly different between the two colitic groups. In addition, colon wet weight, colon length, and histological colitis scores were similar in colitic mice treated with FOS compared to colitic mice without FOS treatment. Colonic claudin mRNA expression was lower in DSS‐treated mice than control mice, but was not significantly altered by FOS treatment. These data suggest that treatment with fructooligosaccharides did not significantly alter susceptibility to DSS‐induced colitis.

Effects of Prebiotic Fructooligosaccharides on Cytokine and Tight Junction Protein Expression in Cultured Intestinal Epithelial Cells

Prebiotic molecules such as fructooligosaccharides (FOS) can promote the growth and metabolism of beneficial bacteria in the host intestine. There are several published studies suggesting that prebiotic supplementation can alleviate symptoms of colitis in animal models. In addition, a recent study showed evidence for direct effects of FOS on tight junction protein expression in cultured intestinal epithelial cells. This study aimed to assess effects of FOS on pro‐inflammatory cytokine and tight junction protein expression in CMT‐93 and Caco‐2 colonic epithelial cells. Cells were treated with 0.1 mg/ml, 1 mg/ml or 10 mg/ml FOS and expression of cyclooxygenase‐2 (COX‐2), pro‐inflammatory cytokines interleukin (IL)‐1β and IL‐6, and tight junction proteins claudin and ZO‐1 were evaluated by real‐time qPCR. The number of viable cells was analyzed after overnight exposure to FOS using a cell survival assay. Expression of ZO‐1 and claudin and localization of nuclear factor kappa‐B (NFkB) were evaluated by immunofluorescent staining. Surprisingly, FOS‐treated CMT‐93 cells showed a slight reduction in claudin mRNA expression compared to untreated cells. ZO‐1 and COX‐2 mRNA expression were not altered by FOS treatment compared to untreated controls. Immunofluorescent staining showed no translocation of NFkB to the nucleus after 2 hours of exposure to FOS. In conclusion, prebiotic fructooligosaccharides had minimal to no effects on the mRNA expression of claudin, ZO‐1, and COX‐2. In addition, FOS did not activate the NFkB pathway at the time points studied. These data suggest that FOS may not cause inflammatory responses in intestinal epithelial cells.

Interleukin-22 plays a protective role in animal model of experimental colitis by signaling on Math1+ cell.

Abstract Interleukin-22 plays both beneficial and deleterious role in intestinal inflammation. Further investigation is required to understand cell target and mechanism of action of IL-22 in large intestine. By using various intestinal cell specific IL-22Ra1 knockout mice models, such as entire intestinal epithelial cell (IL-22Ra1ΔIEC), Paneth (IL-22Ra1ΔDefa6), tamoxifen inducible Lgr5+ intestinal stem cell (IL-22Ra1ΔLgr5) and RU486 inducible secretory cell (IL-22Ra1ΔMath1-PGR). We tried to identify specific cell target of IL-22 in intestine. To induce experimental colitis, 8 days dextran sulphate sodium (DSS, 2%) was provided in drinking water followed by two days of normal water. On assessing colitis severity, more weight loss, histopathological changes and reduced colon length was observed in IL-22ra1ΔIEC mice. Increased expression of inflammatory cytokine genes and Lgr5+ stem cell related Olfm4 transcript were observed in distal colon of IL-22ra1ΔIEC as compared to IL-22ra1fl/fl mice. IL-22Ra1 signaling in IL-22Ra1ΔLgr5 and IL-22Ra1ΔDefa6 mice were dispensable in DSS induced colitis. Although goblet cell number was unaltered, expression of selective glycosyltransferases (causing O-glycosylation of mucin) were significantly reduced in colon of DSS treated IL-22Ra1ΔIEC as compared to IL-22Ra1fl/fl mice. Type-O glycan profile analysis of colon mucin using MALDI-TOF reveal premature termination of core 1 and 2 structure in IL-22Ra1ΔIEC mice as compared to IL-22Ra1fl/fl mice at steady state. Our preliminary data show that IL-22Ra1ΔMath1-PGR mice are more susceptible to DSS induced colitis. IL-22 may act by inducing expression of glycosyltransferases in Math1+ cell to abrogate development of experimental colitis.

Leaky gut model of the human intestinal mucosa for testing siRNA-based nanomedicine targeting JAK1.

Complex in vitro models of human immune cells and intestinal mucosa may have a translation-assisting role in the assessment of anti-inflammatory compounds. Chronic inflammation of the gastrointestinal tract is a hallmark of inflammatory bowel diseases (IBD). In both IBD entities, Crohn's disease and ulcerative colitis, impaired immune cell activation and dysfunctional epithelial barrier are the common pathophysiology. Current therapeutic approaches are targeting single immune modulator molecules to stop disease progression and reduce adverse effects. Such molecular targets can be difficult to assess in experimental animal models of colitis, due to the disease complexity and species differences. Previously, a co-culture model based on human epithelial cells and monocytes arranged in a physiological microenvironment was used to mimic inflamed mucosa for toxicological and permeability studies. The leaky gut model described here, a co-culture of Caco-2, THP-1 and MUTZ-3 cells, was used to mimic IBD-related pathophysiology and for combined investigations of permeability and target engagement of two Janus kinase (JAK) inhibitors, tofacitinib (TOFA) and a JAK1-targeting siRNA nanomedicine. The co-culture just before reaching confluency of the epithelium was used to mimic the compromised intestinal barrier. Delivery efficacy and target engagement against JAK1 was quantified via downstream analysis of STAT1 protein phosphorylation after IFN-γ stimulation. Compared to a tight barrier, the leaky gut model showed 92 ± 5% confluence, a barrier function below 200 Ω*cm2, and enhanced immune response to bacteria-derived lipopolysaccharides. By confocal microscopy we observed an increased accumulation of siJAK1-nanoparticles within the sub-confluent regions leading to uptake into immune cells near the epithelium. A concentration-dependent downregulation of JAK/STAT pathway was observed for siJAK1-nanoparticles (10 ± 12% to 16 ± 12%), whereas TOFA inhibition was 86 ± 2%, compared to untreated cells.By mimicking the status of severely damaged epithelium, like in IBD, the leaky gut model holds promise as a human in vitro system to evaluate the efficacy of anti-inflammatory drugs and nanomedicines.

Lactobacillus plantarum strains attenuated DSS-induced colitis in mice by modulating the gut microbiota and immune response.

Gut microbiota has become a new therapeutic target in the treatment of inflammatory Bowel Disease (IBD). Probiotics are known for their beneficial effects and have shown good efficacy in the clinical treatment of IBD and animal models of colitis. However, how these probiotics contribute to the amelioration of IBD is largely unknown. In the current study, the DSS-induced mouse colitis model was treated with oral administration of Lactobacillus plantarum strains to investigate their effects on colitis. The results indicated that the L. plantarum strains improved dysbiosis and enhanced the abundance of beneficial bacteria related to short-chain fatty acids (SCFAs) production. Moreover, L. plantarum strains decreased the level of pro-inflammatory cytokines, i.e., IL-17A, IL-17F, IL-6, IL-22, and TNF-α and increased the level of anti-inflammatory cytokines, i.e., TGF-β, IL-10. Our result suggests that L. plantarum strains possess probiotic effects and can ameliorate DSS colitis in mice by modulating the resident gut microbiota and immune response.

Therapeutic Evaluation of Fecal Microbiota Transplantation in an Interleukin 10-deficient Mouse Model.

With the development of microecology in recent years, the relationship between intestinal bacteria and inflammatory bowel disease (IBD) has attracted considerable attention. Accumulating evidence suggests that dysbiotic microbiota plays an active role in triggering or worsening the inflammatory process in IBD and that fecal microbiota transplantation (FMT) is an attractive therapeutic strategy since transferring a healthy microbiota to IBD patient could restore the appropriate host-microbiota communication. However, the molecular mechanisms are unclear, and the efficacy of FMT has not been very well established. Thus, further studies in animal models of IBD are necessary. In this method, we applied FMT from wild-type C57BL/6J mice to IL-10 deficient mice, a widely used mouse model of colitis. The study elaborates on collecting fecal pellets from the donor mice, making the fecal solution/suspension, administering the fecal solution, and monitoring the disease. We found that FMT significantly mitigated the cardiac impairment in IL-10 knockout mice, underlining its therapeutic potential for IBD management.

Multi-Omics Analysis of Western-style Diet Increased Susceptibility to Experimental Colitis in Mice.

BackgroundWestern-style diet (WSD) is associated with inflammatory bowel disease (IBD) prevalence. However, the impact of WSD on IBD development and its underlying mechanism remain unclear. Transcriptomics and metabolomics could be beneficial for identifying key factors in WSD-related experimental IBD susceptibility. However, no such study has been conducted yet. We aimed to analyze the implications of WSD for experimental colitis susceptibility in mice and its underlying mechanism using these high-throughput technologies.MethodsWe fed experimental mice a WSD and a control diet from weaning. After 9 weeks, the mice were treated with 2,4,6 trinitrobenzene sulfonic acid to induce colitis, and the control group was treated with 50% ethanol (commonly used IBD animal model). Genome-wide microarray and liquid chromatography-tandem mass spectrometry were used to identify the differential transcripts and metabolites of experimental colitis with and without pre-illness WSD.ResultsWSD induced more severe inflammation in experimental colitis than the control diet. We found 2540 up-regulated genes and 2737 down-regulated genes in experimental colitis with WSD compared with those for the control diet. In addition, levels of 41 colonic tissue metabolites and 56 serum metabolites showed significant differences. Integrating transcriptomic and metabolomic data, we found major co-expression networks through which WSD promoted experimental IBD susceptibility, including enzymes of biotransformation, glycan synthesis and metabolism, steroid hormone metabolites.ConclusionPre-illness WSD increased experimental colitis susceptibility. Our results could provide important evidences for the potential mechanisms and assist dietary recommendations to better manage IBD.

GLP-1 Mediates Regulation of Colonic ACE2 Expression by the Bile Acid Receptor GPBAR1 in Inflammation.

Background & Aims: ACE2, a carboxypeptidase that generates Ang-(1-7) from Ang II, is highly expressed in the lung, small intestine and colon. GPBAR1, is a G protein bile acid receptor that promotes the release of the insulinotropic factor glucagon-like peptide (GLP)-1 and attenuates intestinal inflammation. Methods: We investigated the expression of ACE2, GLP-1 and GPBAR1 in two cohorts of Crohn’s disease (CD) patients and three mouse models of colitis and Gpbar1−/− mice. Activation of GPBAR1 in these models and in vitro was achieved by BAR501, a selective GPBAR1 agonist. Results: In IBD patients, ACE2 mRNA expression was regulated in a site-specific manner in response to inflammation. While expression of ileal ACE2 mRNA was reduced, the colon expression was induced. Colon expression of ACE2 mRNA in IBD correlated with expression of TNF-α and GPBAR1. A positive correlation occurred between GCG and GPBAR1 in human samples and animal models of colitis. In these models, ACE2 mRNA expression was further upregulated by GPABR1 agonism and reversed by exendin-3, a GLP-1 receptor antagonist. In in vitro studies, liraglutide, a GLP-1 analogue, increased the expression of ACE2 in colon epithelial cells/macrophages co-cultures. Conclusions: ACE2 mRNA expression in the colon of IBD patients and rodent models of colitis is regulated in a TNF-α- and GLP-1-dependent manner. We have identified a GPBAR1/GLP-1 mechanism as a positive modulator of ACE2.

Secreted NF-κB suppressive microbial metabolites modulate gut inflammation.

Emerging evidence suggests that microbiome-host crosstalk regulates intestinal immune activity and predisposition to inflammatory bowel disease (IBD). NF-κB is a master regulator of immune function and a validated target for the treatment of IBD. Here, we identify five Clostridium strains that suppress immune-mediated NF-κB activation in epithelial cell lines, PBMCs, and gut epithelial organoids from healthy human subjects and patients with IBD. Cell-free culture supernatant from Clostridium bolteae AHG0001 strain, but not the reference C.bolteae BAA-613 strain, suppresses inflammatory responses and endoplasmic reticulum stress in gut epithelial organoids derived from Winnie mice. The invivo responses to Clostridium bolteae AHG0001 and BAA-613 mirror the invitro activity. Thus, using our invitro screening of bacteria capable of suppressing NF-κB in the context of IBD and using an exvivo organoid-based approach, we identify a strain capable of alleviating colitis in a relevant pre-clinical animal model of IBD.

Targeting the endo-lysosomal autophagy pathway to treat inflammatory bowel diseases

Inflammatory bowel disease (IBD) is a serious public health problem in Western society with a continuing increase in incidence worldwide. Safe, targeted medicines for IBD are not yet available. Autophagy, a vital process implicated in normal cell homeostasis, provides a potential point of entry for the treatment of IBDs, as several autophagy-related genes are associated with IBD risk. We conducted a series of experiments in three distinct mouse models of colitis to test the effectiveness of therapeutic P140, a phosphopeptide that corrects autophagy dysfunctions in other autoimmune and inflammatory diseases. Colitis was experimentally induced in mice by administering dextran sodium sulfate and 2,4,6 trinitrobenzene sulfonic acid. Transgenic mice lacking both il-10 and iRhom2 − involved in tumor necrosis factor α secretion − were also used. In the three models investigated, P140 treatment attenuated the clinical and histological severity of colitis. Post-treatment, altered expression of several macroautophagy and chaperone-mediated autophagy markers, and of pro-inflammatory mediators was corrected. Our results demonstrate that therapeutic intervention with an autophagy modulator improves colitis in animal models. These findings highlight the potential of therapeutic peptide P140 for use in the treatment of IBD.

Evaluation of Protective Effects of Hydroalcoholic Extract Obtained from Cucurbita moschata Skin in Animal Model of Ulcerative Colitis

Evaluation of Protective Effects of Hydroalcoholic Extract Obtained from Cucurbita moschata Skin in Animal Model of Ulcerative Colitis

Ethanolic extract from Lepidium virginicum L. ameliorates DNBS-induced colitis in rats

Ethnopharmacological relevanceLepidium virginicum L. (Brassicaceae) is a plant widely used in traditional Mexican medicine as an expectorant, diuretic, and as a remedy to treat diarrhea and dysentery, infection-derived gastroenteritis. However, there is no scientific study that validates its clinical use as an anti-inflammatory in the intestine. Aim of the studyThis study aimed to investigate the anti-inflammatory properties of the ethanolic extract of Lepidium virginicum L. (ELv) in an animal model of inflammatory bowel disease (IBD)-like colitis. Materials and methodsThe 2,4-dinitrobenzene sulfonic acid (DNBS) animal model of IBD was used. Colitis was induced by intrarectal instillation of 200 mg/kg of DNBS dissolved vehicle, 50% ethanol. Control rats only received the vehicle. Six hours posterior to DNBS administration, ELv (3, 30, or 100 mg/kg) was administered daily by gavage or intraperitoneal injection. The onset and course of the inflammatory response were monitored by assessing weight loss, stool consistency, and fecal blood. Colonic damage was evaluated by colon weight/length ratio, histopathology, colonic myeloperoxidase (MPO) activity, and gene expression of proinflammatory cytokines, including tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), chemokine C-X-C motif ligand 1 (CXCL-1), and interleukin-6 (IL-6). ResultsRats treated with DNBS displayed significant weight loss, diarrhea, fecal blood, colon shortening, a significant increase in immune cell infiltration and MPO activity, as well as increased proinflammatory cytokine expression. Intraperitoneal administration of ELv significantly reduced colon inflammation, whereas oral treatment proved to be ineffective. In fact, intraperitoneal ELv significantly attenuated the clinical manifestations of colitis, immune cell infiltration, MPO activity, and pro-inflammatory (CXCL-1, TNF-α, and IL-1β) gene expression in a dose-dependent manner. ConclusionTraditional medicine has employed ELv as a remedy for common infection-derived gastrointestinal symptoms; however, we hereby present the first published study validating its anti-inflammatory properties in the mitigation of DNBS-induced colitis.

DOP49 Context-dependent roles of High-mobility group box 1 (HMGB1) during intestinal inflammation and carcinogenesis

Abstract Background HMGB1 is a ubiquitously expressed nucleoprotein with proinflammatory functions following cellular release. The protein is passively released during tissue necrosis, acting as a damage-associated molecular pattern, but can also be actively secreted by immune cells. Stool and serum HMGB1 levels have been suggested as markers of both inflammatory bowel disease (IBD) activity and colorectal cancer (CRC) invasiveness, and antibody-mediated HMGB1 neutralization was beneficial in animal models of IBD. We explored context-dependent functions of HMGB1 in the injured intestine using novel experimental mice with cell-specific genetic HMGB1 deficiency. Methods To circumvent the postnatal lethality of global HMGB1 deficiency in animals, we used the Cre-lox system to generate enterocyte-specific (Hmgb1ΔIEC , Villin-Cre) and myeloid cell-specific (Hmgb1ΔLysM , LysM-Cre) HMGB1-knockout mice. Animals were subjected to well-established models of acute (DSS, Citrobacter rodentium) and chronic (AOM+DSS, CD45RBhigh T cell transfer colitis, Apc+/min) intestinal injury, followed by clinical, endoscopic, histological and molecular analysis. HMGB1 expression was assessed in human IBD and CRC specimens. Results IBD and CRC biopsies exhibited high levels of HMGB1 expression in epithelia, immune cells, tumor cells and the peritumoral stroma. HMGB1 deficiency from enterocytes and myeloid cells did not alter Citrobacter- or T cell transfer-induced enterocolitis, when epithelial injury was comparably low. In contrast, Hmgb1ΔIEC mice exhibited aggravated DSS-induced colitis, as evidenced by severe weight loss as well as exacerbated neutrophil- and monocyte-driven mucosal inflammation compared to Hmgb1f/f . Whole tissue RNA sequencing indicated defective cellular proliferation in injured Hmgb1ΔIEC intestines. In the AOM+DSS-model, Hmgb1ΔIEC had a comparable tumor burden to Hmgb1f/f , whereas Hmgb1ΔLysM had significantly fewer and smaller tumors, potentially linked to metabolic alterations in the tumor micromilieu. In the Apc+/min model, enterocyte HMGB1 deficiency effectuated more and larger tumors, whereas leukocyte HMGB1 did not affect tumor load. Conclusion Contrasting antibody-mediated HMGB1 neutralization in animal models of IBD, our findings from genetic HMGB1 deletion studies reveal a critical role of enterocyte HMGB1 in the maintenance of the intestinal barrier during severe colitis. Impaired epithelial regeneration or inefficient local immune cell expansion in Hmgb1ΔIEC may account for the aggravated phenotype. HMGB1 from enterocytes and immune cells context-dependently affect maladaptive intestinal would healing, potentially mediated by cell-intrinsic and -extrinsic mechanisms that warrant further investigation.

Analysis of the Therapeutic Effect of Changyanning on Intestinal Flora in Inflammatory Bowel Disease.

Research Purposes. Inflammatory bowel disease (IBD) is an autoimmune disease coinduced by genes, environment, and immune response, mainly including ulcerative colitis (UC) and Crohn's disease (CD). There are a large number and variety of intestinal bacteria in the human intestinal tract. These bacteria maintain a balance with the human environment and participate in the normal physiological processes of the human body. They play a unique role in defending against pathogen invasion, maintaining the homeostasis of the human immune system and metabolizing substances. Intestinal flora imbalance may be one of the pathogenic factors of IBD, and restoring the disturbed intestinal flora has become a research hotspot in the prevention and treatment of IBD. Changyanning is mainly composed of Dijincao grass, yellow hairy ear grass, camphor tree roots, maple leaves, and so on. Clinical studies have shown that Changyanning alone or in combination has a significant effect on ulcerative colitis, but the treatment mechanism is not yet clear. In this study, we established an IBD animal model to explore the therapeutic mechanism of Changyanning on inflammatory bowel disease and its effect on intestinal flora. Research Methods. Male C57BL/6 SPF mice were given free access to 4% dextran sulfate sodium (DSS) solution for 7 days to establish an ulcerative colitis model. After the model was established, different doses of Changyanning tablets, Changyanning granules, and sulfasalazine were given by gavage for 7 days. The relieving effects of the above drugs on the symptoms of inflammatory bowel disease were evaluated by evaluating the mouse/rat body weight, survival rate, disease activity index, colon length, pathological tissue score, and other indicators. Results. The DSS-induced IBD mouse model showed significant increases in weight loss, DAI score, and pathological score. Both Changyanning tablets and granules can relieve the weight loss of mice, restore the colon length, and protect the colon tissue structure of mice. In reducing DAI and pathological scores in mice, Changyanning granules had a better effect. In conclusion, Changyanning can significantly improve the quality of life of IBD model animals, relieve intestinal inflammatory response, and relieve colonic edema, ulceration, and necrosis. The results show that Changyanning has a certain therapeutic effect on IBD. This study also provides experimental evidence for the application of Changyanning in the treatment of IBD, which is of great significance to its clinical application. The trail is registered in ChiCTR with number (TRN) ChiCTR2000028830.

Characterization and Analysis of the Temporal and Spatial Dynamic of Several Enteritis Modeling Methodologies.

Inflammatory bowel disease (IBD), such as Crohn’s disease and ulcerative colitis, is a complex disease involving genetic, immune, and microbiological factors. A variety of animal models of IBD have been developed to study the pathogenesis of human IBD, but there is no model that can fully represent the complexity of IBD. In this study, we established two acute enteritis models by oral 3% DSS or intraperitoneal injection of anti-CD3 antibody, and two chronic enteritis models by feeding 3 cycles of 1.5% DSS or 3 months of the high-fat diet, respectively, and then examined the clinical parameters, histological changes, and cytokine expression profiles after the successful establishment of the models. Our results indicated that in 3% DSS-induced acute enteritis, the colorectal injury was significantly higher than that of the small intestine, while in anti-CD3 antibody-induced acute enteritis, the small intestine injury was significantly higher than that of colorectal damage. Besides, in the 1.5% DSS-induced chronic enteritis, the damage was mainly concentrated in the colorectal, while the damage caused by long-term HFD-induced chronic enteritis was more focused on the small intestine. Therefore, our work provides a reference for selecting appropriate models when conducting research on factors related to the pathogenesis of IBD or evaluating the potential diagnosis and treatment possibilities of pharmaceuticals.

Claudins: Beyond Tight Junctions in Human IBD and Murine Models.

Claudins are transmembrane proteins constituting one of three tight junction protein families. In patients with inflammatory bowel disease (IBD), disease activity–dependent changes in expression of certain claudins have been noted, thus making certain claudin family members potential therapy targets. A study was undertaken with the aim of exploring expression of claudins in human disease and two different animal models of IBD: dextrane sulfate sodium–induced colitis and adoptive transfer model of colitis. The expression of sealing claudin-1, claudin-3, claudin-4, and claudin-8, and pore-forming claudin-2 in humans and rodents has been evaluated by immunohistochemistry and quantitative polymerase chain reaction. Claudins were expressed by epithelial and cells of mesodermal origin and were found to be situated at the membrane, within the cytoplasm, or within the nuclei. Claudin expression by human mononuclear cells isolated from lamina propria has been confirmed by Western blot and flow cytometry. The claudin expression pattern in uninflamed and inflamed colon varied between species and murine strains. In IBD and both animal models, diverse alterations in claudin expression by epithelial and inflammatory cells were recorded. Tissue mRNA levels for each studied claudin reflected changes within cell lineage and, at the same time, mirrored the ratio between various cell types. Based on the results of the study, it can be concluded that 1) claudins are not expressed exclusively by epithelial cells, but by certain types of cells of mesodermal origin as well; 2) changes in the claudin mRNA level should be interpreted in the context of overall tissue alterations; and 3) both IBD animal models that were analyzed can be used for investigating claudins as a therapy target, respecting their similarities and differences highlighted in this study.

Orally administrated nucleotide-delivery particles from microfluidics for inflammatory bowel disease treatment

Oral administration route for treating inflammatory bowel disease (IBD) is one of the most convenient methods, especially for the chemical molecular drugs and biologics. Attempts to develop applicable oral administration method tend to focus on the construction of functional microcarriers through simple operations and employing innovative but accessible materials. Here, we report a pH-sensitive drug delivery system by microfluidics for oral administration of therapeutic antisense oligonucleotide (ASO) against TNF-α (TNF-α ASO) to treat the IBD. The microfluidics-derived cationic Konjac glucomannan (cKGM) & ASO Nanocomplex-loaded gelatin methacryloyl (GelMA) microparticles are coated by the acid-insoluble shells, i.e. Eudragit FS30D (GelMA MS/EFS & Nano ASO), which can prevent the encapsulated drugs from being early released in the stomach or small intestine, and enhance their selective accumulation in colon, as well as facilitate the macrophage uptake of drugs via receptor-mediated phagocytosis. It is demonstrated that our designed drug-loaded microcarriers can significantly reduce the production of TNF-α in the nidus of the colitis animal models, and effectively alleviate the symptoms of colitis in the mice after oral administration. These properties indicated that this therapeutic ASO oral delivery system can be a promising approach in treating colon-associated diseases.

Ding's herbal enema treats dextran sulfate sodium-induced colitis in mice by regulating the gut microbiota and maintaining the Treg/Th17 cell balance.

Ding's herbal enema (DHEP) is a traditional Chinese medicinal therapy that has been used to treat ulcerative colitis (UC) in China. The present study determined the molecular mechanism of the effect of DHEP in UC treatment. C57BL/6J mice were treated with 3.5% (w/v) dextran sulfate sodium (DSS) for 7 days to establish an animal model of colitis. The mice were divided into five groups (n=5): Control, vehicle, DHEP, mesalazine and β-sitosterol. After oral administration for 7 days, the body weight, disease activity index, histopathology and inflammatory factors were analyzed. The fractions of CD4+Foxp3+ regulatory T (Treg) cells and CD4+IL-17A+ T helper (Th) cells were determined by flow cytometry. Gut microbiota composition was analyzed by next-generation sequencing. The results revealed that DHEP and β-sitosterol could significantly alleviate the symptoms of DSS-induced UC. Furthermore, the levels of IL-6, cyclooxygenase-2, TNF-α and p65 were reduced after administration of DHEP. Additionally, the data indicated that DHEP could increase the abundance of seven operational taxonomic units (OTUs) and decrease the abundance of 12 OTUs in the gut microbiota. The content of short-chain fatty acids in the colon remodeled the balance of Treg/Th17 cells in DSS-induced UC in mice. The present study preliminarily defined the mechanism of action of DHEP in UC that may be associated with the regulation of the gut microbiota composition, and maintenance of the balance between Treg and Th17 cells. Furthermore, β-sitosterol exhibited the same effects with DHEP and it could be a possible substitute for DHEP in UC treatment.