Acute Experimental Colitis Research Articles

Libertellenone M, a diterpene derived from an endophytic fungus Phomopsis sp. S12, protects against DSS-induced colitis via inhibiting both nuclear translocation of NF-κB and NLRP3 inflammasome activation

NLRP3 inflammasome may serve as a potential target for the development of novel therapeutics for inflammatory bowel diseases. In this study, we found that Libertellenone M (Lib M), a secondary metabolite from the endophytic fungus Phomopsis sp. S12, has anti-inflammatory potential both in vitro and in vivo. Lib M selectively inhibited the expression of proinflammatory cytokine IL-1β and IL-18 in LPS-activated macrophages. The cleavage of pro-caspase 1 was remarkably reduced by Lib M in macrophages stimulated with three NLRP3 inflammasome activators. Administering Lib M attenuated dextran sulfate sodium-induced experimental acute colitis in mice and significantly reduced the production of these cytokines and cleaved caspase 1 in colon tissues. Apart from inhibition of NLRP3 inflammasome assembly, Lib M also suppressed NF-κB nuclear translocation in macrophages. Taken together, these findings suggest that Lib M-mediated inhibition of NLRP3 inflammasome activation could protect against colitis-like inflammatory diseases, and that this compound derived from a plant-associated fungus might inspire the exploration of novel immunosuppressive agents.

Rho kinase Blockade Ameliorates DSS-Induced Ulcerative Colitis in Mice Through Dual Inhibition of the NF-κB and IL-6/STAT3 Pathways.

Inflammatory bowel disease (IBD) has received much attention due to its increasing worldwide incidence and potential increased risk of colorectal cancer. The protective function of a Rho-associated protein kinase inhibitor (Y-27632) against 2,4,6-trinitrobenzene sulfonic acid (TNBS) induced mouse colitis has been proven in previous studies, but the concrete therapeutic mechanism of Y-27632 is still not completely illuminated. This current research is intended for further investigation of the effect and mechanism of Y-27632 in a mouse model of acute experimental ulcerative colitis induced by dextran sulfate sodium (DSS). A total of 24 male BALB/c mice were randomly separated into the following three groups (n = 8 per group) and injected intraperitoneally with the corresponding reagents for 7days: control group (PBS), DSS group (PBS), and Y-27632 group (PBS and Y-27632; 10mg/kg). Our data indicated that Y-27632 could significantly improve the severity of colitis, as evidenced by the disease activity index (DAI) scores, histological damage, and colon length. Additionally, Y-27632 treatment significantly decreased CD68 and proinflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-17F (IL-17F), and interleukin-6 (IL-6). Furthermore, Y-27632 potently and pleiotropically suppressed nuclear factor-κB (NF-κB) and signal transduction and transcriptional activator 3 (STAT3) activation as well as the activity of prosurvival genes that are dependent on these transcription factors. In summary, the study demonstrates that Y-27632 exerts ameliorative effects on colonic inflammation mediated through dual inhibition of the NF-κB and IL-6/STAT3 pathways and thus is likely to function as a prospective novel treatment for human ulcerative colitis (UC).

Novel Histone Deacetylase 6 Inhibitor CKD-506 Inhibits NF-κB Signaling in Intestinal Epithelial Cells and Macrophages and Ameliorates Acute and Chronic Murine Colitis.

Selective blocking of HDAC6 has become a promising strategy in treating inflammatory bowel disease. CKD-506 is a novel isoform-selective inhibitor of histone deacetylase 6. The present study was performed to evaluate the effect of CKD-506 on the NF-κB signaling pathway in intestinal epithelial cells (IECs) and macrophages and on murine models of acute and chronic colitis. RAW264RAW264.7 murine macrophages and COLO 205 human IECs were pretreated with CKD-506 and then stimulated with lipopolysaccharides (LPS). Cytokine expression of TNF-α, interleukin (IL)-6, IL-8, and IL-10 was measured by ELISA. The effect of CKD-506 on NF-κB signaling was evaluated by Western blotting of IκBα phosphorylation/degradation and electrophoretic mobility shift assay. In vivo studies were performed using a dextran sulfate sodium (DSS)-induced acute colitis model, a chronic colitis model in IL-10 knockout mice, and an adoptive transfer model. Colitis was quantified by the disease activity index, colon length, and histopathologic evaluation. CKD-506 suppressed the expression of pro-inflammatory cytokines such as IL-6, IL-8, and TNF-α in IECs and macrophages. CKD-506 strongly inhibited IκBα phosphorylation/degradation and the DNA-binding activity of NF-κB. Oral administration of CKD-506 attenuated DSS-induced acute colitis and chronic colitis in IL-10-/- and adoptive transfer models. CKD-506 ameliorated weight loss, disease activity, and histopathologic score in colitis mice and downregulated IκBα phosphorylation and pro-inflammatory cytokine production significantly. CKD-506 blocked NF-κB signaling in IECs and macrophages and ameliorated experimental acute and chronic murine colitis models, which suggests that CKD-506 is a promising candidate for inflammatory bowel disease treatment as a small molecular medicine.

Effect of Electroacupuncture in Mice with Dextran Sulfate Sodium-Induced Colitis and the Influence of Gut Microbiota.

Background The relationship between inflammatory bowel disease and gut microbiota is inextricable. Electroacupuncture (EA) can alleviate acute experimental colitis, but the performance of intestinal microorganisms and the mechanism are still not fully understood. We investigated the relationship between the EA and gut microbes and clarified the role of tight junction and adiponectin in the anti-inflammatory effect of EA. Methods Male C57BL/6 mice were randomized into three groups: normal control, dextran sulfate sodium- (DSS-) induced ulcerative colitis (DSS), and DSS with EA ST36 (DSS + EA). Mice body weight, DAI score, colon length, and histological score were evaluated for colitis severity. Colonic inflammation and tight junctions were demonstrated by the immunohistochemical (IHC) method. Systemic responses were confirmed by plasma cytokines and adiponectin with multiplex immunoassays. Gut microbiome profiling was conducted by 16S rRNA gene sequencing. Results EA had benefit in relieving both macroscopic and microscopic colonic inflammation. It can reduce disease activity, maintain colon length, and ameliorate histological inflammatory reaction. In IHC stain, EA decreased CD11b, F4/80, TLR4, and MyD88 and preserved claudin-1 and ZO-1 expression. Compared with the control group, the DSS group showed elevated levels of CRP, IFN-γ, TNF-α, and IL-6, but decreased adiponectin. These changes were reversed by EA, accompanied by modulation of the overall structure of gut microbiota. Conclusion Our findings suggest that EA exerts its therapeutic effect by TLR4 signaling via the MyD88-dependent pathway. EA could increase adiponectin, maintain mucosal tight junctions, and modulate gut microbiota.

Formyl peptide receptor 2 regulates monocyte recruitment to promote intestinal mucosal wound repair.

Mucosal wound repair is coordinated by dynamic crosstalk between endogenous and exogenous mediators and specific receptors on epithelial cells and infiltrating immune cells. One class of such receptor-ligand pairs involves formyl peptide receptors (FPRs) that have been shown to influence inflammatory response and repair. Here we explored the role of murine Fpr2/3, an ortholog of human FPR2/receptor for lipoxin A4 (ALX), in orchestrating intestinal mucosal repair. Compared with wild-type (WT) mice, Fpr2/3-/- mice exhibited delayed recovery from acute experimental colitis and perturbed repair after biopsy-induced colonic mucosal injury. Decreased numbers of infiltrating monocytes were observed in healing wounds from Fpr2/3-/- mice compared with WT animals. Bone marrow transplant experiments revealed that Fpr2/3-/- monocytes showed a competitive disadvantage when infiltrating colonic wounds. Moreover, Fpr2/3-/- monocytes were defective in chemotactic responses to the chemokine CC chemokine ligand (CCL)20, which is up-regulated during early phases of inflammation. Analysis of Fpr2/3-/- monocytes revealed altered expression of the CCL20 receptor CC chemokine receptor (CCR)6, suggesting that Fpr2/3 regulates CCL20-CCR6-mediated monocyte chemotaxis to sites of mucosal injury in the gut. These findings demonstrate an important contribution of Fpr2/3 in facilitating monocyte recruitment to sites of mucosal injury to influence wound repair.-Birkl, D., O'Leary, M. N., Quiros, M., Azcutia, V., Schaller, M., Reed, M., Nishio, H., Keeney, J., Neish, A. S., Lukacs, N. W., Parkos, C. A., Nusrat, A. Formyl peptide receptor 2 regulates monocyte recruitment to promote intestinal mucosal wound repair.

Fecal Microbiota Transplantation Controls Murine Chronic Intestinal Inflammation by Modulating Immune Cell Functions and Gut Microbiota Composition.

Different gastrointestinal disorders, including inflammatory bowel diseases (IBD), have been linked to alterations of the gut microbiota composition, namely dysbiosis. Fecal microbiota transplantation (FMT) is considered an encouraging therapeutic approach for ulcerative colitis patients, mostly as a consequence of normobiosis restoration. We recently showed that therapeutic effects of FMT during acute experimental colitis are linked to functional modulation of the mucosal immune system and of the gut microbiota composition. Here we analysed the effects of therapeutic FMT administration during chronic experimental colitis, a condition more similar to that of IBD patients, on immune-mediated mucosal inflammatory pathways. Mucus and feces from normobiotic donors were orally administered to mice with established chronic Dextran Sodium Sulphate (DSS)-induced colitis. Immunophenotypes and functions of infiltrating colonic immune cells were evaluated by cytofluorimetric analysis. Compositional differences in the intestinal microbiome were analyzed by 16S rRNA sequencing. Therapeutic FMT in mice undergoing chronic intestinal inflammation was capable to decrease colonic inflammation by modulating the expression of pro-inflammatory genes, antimicrobial peptides, and mucins. Innate and adaptive mucosal immune cells manifested a reduced pro-inflammatory profile in FMT-treated mice. Finally, restoration of a normobiotic core ecology contributed to the resolution of inflammation. Thus, FMT is capable of controlling chronic intestinal experimental colitis by inducing a concerted activation of anti-inflammatory immune pathways, mechanistically supporting the positive results of FMT treatment reported in ulcerative colitis patients.

Roseburia intestinalis inhibits oncostatin M and maintains tight junction integrity in a murine model of acute experimental colitis

Objective: Levels of oncostatin M (OSM) and the composition of gut microbiota predict responses to anti-TNF agents used for IBD therapy. Here, the aim was to investigate the effects of Roseburia intestinalis, a gut microbiota, on OSM and on intestinal barrier in colitis.Methods: In the murine model of 3% dextran sulfate sodium (DSS)-induced colitis, we tested disease activity index (DAI), colon length, histological score and expression of tight junction (TJ) proteins (ZO-1, occludin and claudin-1), OSM, TNF-α and TLR5. In addition, a cellular model was used to examine the role of R. intestinalis during secretion of OSM by lipopolysaccharide (LPS)-induced bone marrow-derived macrophages (BMDMs) isolated from wild-type (WT) and TLR5 knockout (TLR5 KO) mice. Furthermore, we evaluated the impact of OSM on expressions of TJ proteins by Caco-2 cells.Results: R. intestinalis in DSS-induced colitis decreased DAI score (p < .001), colon length shortening (6.46 ± 0.36 cm vs 5.65 ± 0.47 cm, p = .022), histological score (2.667 ± 1.15 vs 5.33 ± 1.14, p = .018) and increased expression of TJ proteins (p < .05). In addition, R. intestinalis reduced expression of OSM (p < .05) and TNF-α (p < .05), while increasing expression of TLR5 (p < .05). Furthermore, R. intestinalis reduced secretion of OSM (p < .05) by LPS-induced BMDMs isolated from WT and TLR5 KO mice. Moreover, OSM downregulated expression of TJ proteins (p < .05) by Caco-2 cells in a concentration-dependent manner.Conclusions: These results indicate that R. intestinalis attenuates inflammation in IBD by decreasing secretion of OSM and by promoting intestinal barrier function. Taken together, the data provide insight into the role of the gut microbiota in patients with IBD who are resistant to anti-TNF therapy.

Network pharmacology-based identification of the protective mechanisms of taraxasterol in experimental colitis

Background and aimTaraxasterol, a pentacyclic-triterpene, has been reported to exert potent anti-inflammatory activity. However, the molecular mechanisms by which taraxasterol attenuates acute experimental colitis (AEC) remain undocumented. MethodsA network pharmacology approach was used to identify the candidate and collective targets of taraxasterol and acute colitis, and an AEC model was established by oral administration of dextran sulfate sodium (DSS) in mice. Body weight and colon lengths were then examined, the pathological scoring was assessed by using hematoxylin and eosin staining, and the expression levels of target genes were further confirmed by qRT-PCR and immunohistochemistry (IHC) analysis in taraxasterol treated AEC models. Results14 collective targets of taraxasterol and acute colitis were identified by a network pharmacology analysis, including PPARG, JAK2, MMP3, NR1I2 and PTPN11. Further investigations in an AEC model showed that, taraxasterol alleviated the unfavorable clinical symptoms and attenuated the intestinal inflammation response by reducing the cytokines TNF-α, IL-1β and IL-6 levels. qRT-PCR and IHC analysis evidenced that, taraxasterol decreased MMP3 expression levels, but increased PPARG expression levels in AEC models as compared with the DSS group. ConclusionsOur findings demonstrated that taraxasterol improved DSS-induced AEC through regulating MMP3 and PPARG expression, providing a new insight into the potential therapeutic strategies for acute colitis.

P097 Intestinal barrier dysfunction in association with fibrosis during experimental acute and chronic colitis in mice

P097 Intestinal barrier dysfunction in association with fibrosis during experimental acute and chronic colitis in mice

Electroacupuncture at ST-36 ameliorates DSS-induced acute colitis via regulating macrophage polarization induced by suppressing NLRP3/IL-1β and promoting Nrf2/HO-1

BackgroundElectroacupuncture (EA) at ST-36 can attenuate acute experimental colitis, but the mechanisms are unclear. We investigated the role of macrophages in the anti-inflammatory effects of EA and its molecular mechanisms. MethodsMale C57BL/6 mice were randomized into five groups: normal control, dextran sulfate sodium (DSS)-induced acute colitis (DSS), DSS with sham EA (SEA), DSS with high-frequency EA (HEA) and DSS with low-frequency EA (LEA). Body weight, colon length, DAI score and histological score were evaluated during colitis progression. Serum and colonic levels of pro- and anti-inflammatory cytokines were detected with ELISA, cytometric beads array, RT-PCR and western blotting analysis. Colonic macrophage subsets were determined using flow cytometry. Magnetic-activated cell sorting was applied to isolate colonic macrophages, and molecular mechanisms were explored with western blotting, RT-PCR and immunofluorescence. Results(1) Compared with the DSS group, HEA and LEA attenuated body weight loss and decreased DAI and histological scores. (2) Serum levels and colonic protein and mRNA levels of IL-1β, TNFα, IL-6, IL-12 and IL17 were markedly decreased with HEA and LEA. IL-10 level was increased with HEA. (3) M1 macrophage percentage increased, while M2 macrophage percentage decreased in the DSS group; HEA and LEA reversed these proportions. (4) NLRP3/IL-1β protein and mRNA levels in isolated macrophages decreased with HEA and LEA compared with the DSS treatment group; (5) HEA increased Nrf2/HO-1 levels compared with levels in DSS mice. ConclusionThe anti-inflammatory effects of EA on DSS-induced acute colitis may rely on regulating macrophage polarization, NLRP3/IL-1β suppression and Nrf2/HO-1 promotion.

Is dextran sulfate sodium a good inducer of acute experimental enteritis?

Animal models play critical roles in exploring the pathogenesis of human diseases and designing novel therapeutic schemes. Acute experimental colitis (AEC) models have been reported to be established in mice principally by oral administration of dextran sulfate sodium (DSS). However, little knowledge is known about whether DSS can be used to induce the acute experimental enteritis (AEE). In this study, different concentrations of DSS (0%, 2%, 3%, and 5%) were used to induce AEC and AEE models in two cohorts. After the establishment of these two models, the symptoms of the mice induced by DSS were noted, the length and average weight of each colon and small intestine were measured, and hematoxylin and eosin (HE) staining was conducted for assessing the inflammatory infiltration in these models. Generally, the comparison of the inflammatory scoring between AEC and AEE models was analyzed. As a consequence, we found that, the mice with 2%–5% DSS administration in a week could develop into AEC models in two cohorts and AEE models in one cohort, followed by the signs of diarrhea, gross rectal bleeding, weight loss of the body, and shortened colon and intestine length, as compared with the control group. HE staining showed that the inflammatory scoring was dramatically increased by 3%–5% DSS in AEC models in two cohorts but slightly elevated in AEE models in one cohort. Meanwhile, as compared with the severe AEC models, the extent of inflammatory infiltration induced by 3%–5% DSS in AEE models was much milder. In conclusion, oral administration of 3%–5% DSS is a good inducer of AEC models, but not AEE models.

Morphology of the thymus and the specific features of its cellular composition in experimental acute and chronic ulcerative colitis

To investigate morphological changes in the thymus, the subpopulation composition of lymphocytes and its non-lymphoid cells in dextran-induced experimental acute ulcerative colitis and in different periods of chronic ulcerative colitis. Acute and chronic ulcerative colitis was simulated in C57BL/6 mice, by replacing drinking water with a 1% aqueous dextran sulfate sodium solution. Thymic changes were morphometrically assessed; the number and absolute area of thymic corpuscles and epithelial cells were calculated; and the subpopulation composition of lymphocytes and thymic stromal cells was determined using flow cytofluorimetry; the Kruskal-Wallis test and the Mann-Whitney test were used to compare the groups. In acute catarrhal and ulcerative colitis, there was acute accidental thymic involution with devastation of the cortical substance and with a decline in its volume fraction, with an increase in the levels of cells dying through the mechanism of apoptosis, and with a decrease in the absolute number of lymphocytes, T-helper cells, cytotoxic T-cells, regulatory T-lymphocytes, B-lymphocytes, and dendritic cells, with a rise in the index of the area of thymic corpuscles and in the content of late-phase corpuscles among them, and with the appearance of thymic corpuscles as cyst-like cavities. In chronic ulcerative colitis, the cortex was expanded and the area of thymic corpuscles and the count of medullary epithelial cells increased. The cyst-like thymic corpuscles formed clusters, the count of dendritic cells increased in early-stage chronic ulcerative colitis, but the levels of macrophages decreased in both periods of its development. There is acute accidental involution and thymic hyperplasia with an increase in medullary epithelial cells and thymic corpuscles consisting of cytokeratin 19+ in the epithelial cells in experimental acute and chronic ulcerative colitis, respectively. The more pronounced epithelial cell response found in end-stage experimental chronic ulcerative colitis reflects the enhanced differentiation of regulatory T-lymphocytes and the larger number of which is observed in peripheral blood and in the focus of inflammation in patients with ulcerative colitis, according to the literature.

Sex-Related Differences in the Morphology and Subpopulation Composition of Colon Lymphocytes in Experimental Acute Colitis.

Morphological manifestations of acute colitis and subpopulation composition of colon lymphocytes were studied in male and female C57Bl/6 mice with acute dextran-induced colitis. We evaluated the severity of colitis symptoms, morphological changes in the colon, and prevalence of epithelialized and non-epithelialized ulcers. The subpopulation composition of lymphocytes (CD3-CD19+ B cells, CD3+CD4+ T helpers, CD3+CD8+ cytotoxic T cells, and CD4+CD25+FOXP3+ regulatory T cells) was assessed by flow cytofluorometry in suspension of colon cells prepared by enzymatic disintegration. In males, clinical manifestations of acute colitis and morphological changes were more severe and the prevalence of non-epithelialized ulcers was higher than in females. In females, the content of T, B, and regulatory T cells in the colon wall was higher, while the content of cytotoxic T cells was lower than in males. In females with acute colitis, the absolute lymphocyte count and the content of B cells and regulatory T cells decreased, while the percentage of cytotoxic T cells increased in comparison with intact animals. In males with acute colitis, the levels of regulatory T and B cells increased in comparison with the corresponding parameter in intact animals. Morphological changes and changes in the lymphocyte subpopulations, detected in males and females with acute colitis, were determined by different levels of sex steroid hormones.

Expression of Mucins and Claudins in the Colon during Acute and Chronic Experimental Colitis.

We studied changes in the expression of mRNA for mucins and claudins in the medial part of the colon in male C57Bl/6 mice on the model of acute and chronic colitis induced by substitution of drinking water with 1% solution of dextran sodium sulphate for 5 days. In acute colitis, the expression of the main structural component of glycocalyx, mucin Muc3, decreased and expression of pore-forming claudin Cldn2 increased, which reflected enhanced permeability of tight junctions. In the chronic colitis group, in comparison with the normal group, we observed an increase in expression of mRNA of main structural mucus component Muc2, enhanced of expression of Muc1 associated with carcinogenesis, and reduced expression of Muc13, which led to a more severe course of colitis; the expression of pore-forming claudin Cldn2 was elevated. These findings indicate that the imbalance in the expression of mucins and claudins plays an important role in the mechanisms of development of acute and chronic colitis.

COMP-angiopoietin-1 ameliorates inflammation-induced lymphangiogenesis in dextran sulfate sodium (DSS)-induced colitis model

Alterations in the intestinal lymphatic network are pathological processes as related to inflammatory bowel disease (IBD). In this study, we demonstrated that reduction in inflammation-induced lymphangiogenesis ameliorates experimental acute colitis. A soluble and stable angiopoietin-1 (Ang1) variant, COMP-Ang1, possesses anti-inflammatory and angiogenic effects. We investigated the effects of COMP-Ang1 on an experimental colonic inflammation model. Experimental colitis was induced in mice by administering 3% dextran sulfate sodium (DSS) via drinking water. We determined body weight, disease activity indices, histopathological scores, lymphatic density, anti-ER-HR3 staining, and the expression of members of the vascular endothelial growth factor (VEGF) family and various inflammatory cytokines in the mice. The density of lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1) and VEGFR-3-positive lymphatic vessels increased in mice with DSS-induced colitis. We observed that COMP-Ang1-treated mice showed less weight loss, fewer clinical signs of colitis, and longer colons than Ade-DSS-treated mice. COMP-Ang1 also significantly reduced the density of LYVE-1-positive lymphatic vessels and the disruption of colonic architecture that is normally associated with colitis and repressed the immunoregulatory response. Further, COMP-Ang1 treatment reduced both M1 and M2 macrophage infiltration into the inflamed colon, which involved inhibition of VEGF-C and D expression. Thus, COMP-Ang1, which acts by reducing inflammation-induced lymphangiogenesis, may be used as a novel therapeutic for the treatment of IBD and other inflammatory diseases.Key messagesCOMP-Ang1 decreases inflammatory-induced lymphangiogenesis in experimental acute colitis.COMP-Ang1 improves the symptom of DSS-induced inflammatory response.COMP-Ang1 reduces the expression of pro-inflammatory cytokines in inflamed colon.COMP-Ang1 reduces the expression of VEGFs in inflamed colon.COMP-Ang1 prevents infiltration of macrophages in a DSS-induced colitis model.

Anti-inflammatory actions of Caesalpinin M2 in experimental colitis as a selective glucocoricoid receptor modulator

Although repression of inflammatory gene expression makes glucocorticoids (GCs) powerful anti-inflammatory agents, side effects limit usage and drive the search for improved glucocorticoid receptor (GR) ligands. It has been postulated that the anti-inflammatory effects of GCs are primarily mediated by GR’s activity in transrepressing major inflammation pathways such as NF-κB pathway, whereas their side effects are mostly mediated by GR’s transactivation. In this study, we found that Caesalpinin M2 (C-M2), a cassane furanoditerpene isolated from a Chinese medical plant, exerts an anti-inflammatory potential both in vitro and in vivo. C-M2 inhibited the expression of proinflammatory cytokine IL-1β and IL-6 in LPS-activated bone marrow-derived macrophages. Meanwhile, C-M2 treatment attenuated DSS-induced experimental acute colitis in mice and did not cause side effects, such as spleen involution, like dexamethasone treatment. Molecular docking and cellular thermal shift assay demonstrated that C-M2 could bind to GR in the ligand binding site. We showed that C-M2 mediates gene-inhibitory effects by activating GR. More importantly, C-M2 failed to induce GR binding to glucocorticoid response element-dependent genes and in turn activate their transcription. But it did repress NF-κB-dependent transcription by facilitating the interaction between GR and p65. Taken together, this non-steroidal compound of plant origin may exert anti-inflammatory actions as a selective GR modulator and might hold great potential for therapeutic use in inflammatory diseases.

The octapetide NAP alleviates intestinal and extra-intestinal anti-inflammatory sequelae of acute experimental colitis

The octapeptide NAP has been shown to exert neuroprotective properties and reduce neuro-inflammatory responses. The aim of the present study was to investigate if NAP provides anti-inflammatory effects in acute murine colitis. To address this, C57BL/6 j mice were challenged with 3.5% dextran sulfate sodium from day 0 until day 6 to induce colitis, either treated intraperitoneally with NAP or placebo (NaCl 0.9%) from day 1 until day 6 post-induction (p.i.) and subjected to in depth macroscopic, microscopic and immunological evaluations. Whereas NAP application did not alleviate macroscopic (i.e. clinical) sequelae of colitis, lower numbers of apoptotic, but higher counts of proliferating/regenerating colonic epithelial cells could be observed in NAP as compared to placebo treated mice at day 7 p.i. Furthermore, lower numbers of adaptive immune cells such as T lymphocytes and regulatory T cells were abundant in the colonic mucosa and lamina propria upon NAP versus placebo treatment that were accompanied by less colonic secretion of pro-inflammatory mediators including IFN-γ and nitric oxide at day 7 p.i. In mesenteric lymph nodes, pro-inflammatory IFN-γ, TNF and IL-6 concentrations were increased in placebo, but not NAP treated mice at day 7 p.i., whereas interestingly, elevated anti-inflammatory IL-10 levels could be observed in NAP treated mice only. The assessed anti-inflammatory properties of NAP were not restricted to the intestinal tract, given that in extra-intestinal compartments such as the kidneys, IFN-γ levels increased in placebo, but not NAP treated mice upon colitis induction. NAP induced effects were accompanied by distinct changes in intestinal microbiota composition, given that colonic luminal loads of bifidobacteria, regarded as anti-inflammatory, “health-promoting” commensal species, were two orders of magnitude higher in NAP as compared to placebo treated mice and even naive controls. In conclusion, NAP alleviates intestinal and extra-intestinal pro-inflammatory sequelae of acute experimental colitis and may provide novel treatment options of intestinal inflammatory diseases in humans.

Hyperoside attenuates dextran sulfate sodium-induced colitis in mice possibly via activation of the Nrf2 signalling pathway

BackgroundHyperoside (Hyp) is a flavonoid glycoside compound that has been demonstrated to have anti-inflammatory, anti-apoptotic and antioxidant effects. However, the impact of Hyp on inflammatory bowel disease (IBD) has not been previously explored. Thus, we evaluated the role of Hyp in dextran sodium sulfate (DSS)-induced acute colitis in mice.MethodsWe established a mouse model of experimental acute colitis by treating mice with drinking water supplemented with 3.0% DSS for 7 days. The disease activity index (DAI), colon length, histological features and colonic malondialdehyde (MDA) levels were examined using appropriate methods, and COX-2 expression was examined by immunohistochemistry. TNF-α, IL-4, IL-6, IL-10, NF-κB p65, Bcl-2, Bax, Caspase-3, nuclear factor-erythroid 2-related factor 2 (Nrf2), hemeoxygenase-1 (HO-1) and superoxide dismutase (SOD) levels in colorectal tissues were detected by RT-PCR and western blotting.ResultsHyp significantly attenuated DSS-induced changes in the DAI as well as DSS-induced colonic shortening and histological changes. Hyp also inhibited inflammation, a change reflected by decreases in TNF-α, IL-6, COX-2 and NF-κB p65 expression and increases in IL-10 expression. Hyp suppressed increases in the levels of apoptosis-related proteins, such as Caspase-3 and Bax, but upregulated the level of the anti-apoptotic protein Bcl2. In addition, Hyp also exerted antioxidant effects. The MDA content was decreased, and the expression of Nrf2 and its downstream targets HO-1 and SOD were increased by Hyp.ConclusionsBased on these findings, Hyp possesses the ability to attenuate colitis, possibly by mitigating colonic inflammation and apoptosis via activation of the Nrf2 signaling pathway.

Effect of methanolic extract of Cissampelos pareira on Acetic acid and Dextran Sodium Sulphate (DSS) induced inflammatory bowel disease (IBD) in albino rats and mice

Effect of methanolic extract of Cissampelos pareira (CPME) (200, 400 mg/kg, PO) was studied on acetic acid and DSS induced colitis in rats and mice respectively. Montelukast (20 mg/kg, PO) was used as a Standard drug. At the end of experiment various parameters like scoring for colon, Disease activity index (DAI) which took into account body weight, stool consistency, gross bleeding, Alkaline phosphate (ALP), Erythrocyte Sedimentation Rate (ESR), white blood cell (WBC) count and myeloperoxydase (MPO) activity were measured. Treatment with CP (200,400 mg/kg, PO) decreased significantly macroscopic damage in both models. Histological analysis showed that both doses of the extract improved the microscopic structure and preserved some areas of the colonic mucosa structure. MPO, as a marker of neutrophils infiltration was decreased in a dose-dependent way. In addition DAI, WBC count, ESR and ALP activity also significantly decreases in both doses of CP (p < 0.05, p < 0.01 respectively) in both models. So, from our study we found that CP exerts marked protective effects in acute experimental colitis and may be used clinically in treatment of IBD. This protective effect may be due to the regulations of the productions and an expression of inflammatory mediators.

Morphological Changes in the Thymus, Composition of Its Cells, and Subpopulations of Peripheral Blood Lymphocytes during Experimental Acute Ulcerative Colitis.

Morphological changes in the thymus and composition of its cells and peripheral blood lymphocytes were studied in experiments on C57Bl/6 mice with sodium dextran sulfate-induced acute ulcerative colitis. Severe acute ulcerative colitis in rats was accompanied by stage III-IV accidental involution of the thymus. This state was characterized by inversion of the layers, death of thymocytes, and increase in the number and area of thymic corpuscles from CK19+ epithelial cells. Flow cytofluorometry revealed an increase in the relative number of F4/80+ macrophages in the thymus stroma and CD4-CD8-CD45+CD11c+ dendritic cells and CD326+UEA+CD205- epithelial cells in the medulla. By contrast, the count of CD326+UEA-CD205+ epithelial cells remained unchanged in the cortex. Accidental involution of the thymus was accompanied by an increase in the number of apoptotic AnnV+PI- cells, but decrease in the count of lymphocytes, CD3-CD19+ B lymphocytes, CD3+CD8+ cytotoxic T lymphocytes, immature CD4+CD8+ lymphocytes, and CD3+CD4+ T helpers. The level of peripheral blood endotoxin in adult male C57Bl/6 mice with fibrinous ulcerative colitis was 10-fold lower than in the control. Moreover, we observed a decrease in the absolute number of leukocytes, lymphocytes, CD3+CD4+ T helpers, CD3+CD8+ cytotoxic T lymphocytes, CD4+CD25+FOXP3+ regulatory T lymphocytes, and CD3-CD19+ B lymphocytes in the peripheral blood of animals.