Colonic Tissue Injury Research Articles

Evaluation of the Effects of Different Bacteroides vulgatus Strains against DSS-Induced Colitis.

Although the strain-dependent effects of Bacteroides vulgatus on alleviating intestinal inflammatory diseases have been demonstrated, the literature has rarely focused on the underlying causes of this effect. In this study, we selected four B. vulgatus strains (FTJS5K1, FTJS7K1, FSDTA11B14, and FSDLZ51K1) with different genomic characteristics and evaluated their protective roles against dextran sulfate sodium- (DSS-) induced colitis. Compared to the other three tested strains, B. vulgatus 7K1 more strongly ameliorated the DSS-induced weight loss, shortening of the colon length, increased disease activity index scores, colonic tissue injury, and immunomodulatory disorder. In contrast, B. vulgatus 51K1 significantly worsened the DSS-induced alterations in the tumor necrosis factor-alpha (TNF-α) concentration and colonic histopathology. A comparative genomic analysis of B. vulgatus 7K1 and 51K1 showed that the beneficial effects of B. vulgatus 7K1 may be associated with some of its specific genes involved in the production of short-chain fatty acids or capsular polysaccharides and enhancement of its survivability in the gut. In conclusion, these findings indicate that the supplementation of B. vulgatus 7K1 is a potentially efficacious intervention for alleviating colitis and provides scientific support for the screening of probiotics with anticolitis effect.

Alisol B 23-Acetate Ameliorates Azoxymethane/Dextran Sodium Sulfate-Induced Male Murine Colitis-Associated Colorectal Cancer via Modulating the Composition of Gut Microbiota and Improving Intestinal Barrier.

Hunting for natural compounds that can modulate the structure of the intestinal flora is a new hotspot for colitis‐associated cancer (CAC) prevention or treatment. Alisol B 23-acetate (AB23A) is a natural tetracyclic triterpenoid found in Alismatis rhizoma which is well known for dietary herb. Alismatis rhizoma is often used clinically to treat gastrointestinal diseases in China. In this study, we investigated the potential prevention of AB23A in male mouse models of azoxymethane (AOM) and dextran sulfate sodium (DSS)-induced CAC. AB23A intervention alleviated the body weight loss, disease activity index, colon tumor load, tissue injury, and inflammatory cytokine changes in CAC mice. AB23A intervention leads to remarkable reductions in the activation of TLR, NF-κB and MAPK. AB23A significantly decreased the phosphorylation of p38, ERK, and JNK and up-regulated mucin-2 and the expression of tight junction proteins. The gut microbiota of AB23A-interfered mice was characterized with high microbial diversity, the reduced expansion of pathogenic bacteria, such as Klebsiella, Citrobacter, and Akkermansia, and the increased growth of bacteria including Bacteroides, Lactobacillus, and Alloprevotella. These data reveal that AB23A has the potential to be used to treat CAC in the future.

Walnut green husk polysaccharides prevent obesity, chronic inflammatory responses, nonalcoholic fatty liver disease and colonic tissue damage in high-fat diet fed rats

High-fat (HF) diets cause obesity, gut microbial dysbiosis and associated disorders and inflammatory bowel disease (IBD) due to increased intestinal permeability, which is an important reason for chronic inflammation and oxidative stress. This study was to investigate the effects and mechanism by which walnut green husk polysaccharides (WGHP) prevents obesity, oxidative stress, inflammation, liver and colon damage in HF diet induced rats. We found that WGHP alleviated HF-induced abnormal weight gain, disordered lipid metabolism, inflammation, oxidative stress, colonic tissue injury and up-regulate the expression level of colonic tight junction protein in the rats. Besides, the administration of WGHP promoted browning of iWAT and thermogenesis in BAT of HF-fed rats, and improved gut microbiota dysbiosis by increasing the bacterial diversity and reducing the relative abundance of potential pathogenic bacteria in the colon of the rats. Furthermore, WGHP consumption not only increased the SCFAs content but also improved the relative abundance of Prevotellaceae and Allobaculum in the gut of rats. Our results suggest that the protective effect of WGHP on metabolic inflammation caused by HF may be due to the regulation of gut microbiota and SCFAs.

Effect of acupoint catgut embedding on intestinal mucosal epithelial barrier in ulcerative colitis rats

To observe the effect of acupoint catgut embedding on intestinal mucosal epithelial injury, and expression of epithelial tight junction proteins and mRNAs and protein kinase C(PKC) protein (intestinal mucosal epithelial barrier-related molecules) in rats with experimental ulcerative colitis (UC) of "deficiency-stasis" type, so as to explore its mechanisms underlying improvement of UC. Male SD rats were randomly divided into normal control, UC model, medication (sulfasalazine, SASP) and catgut-embedding groups. The "deficiency-stasis" type UC model was established by gavage of adenine (10 mL/kg) for 2 weeks, cold Folium Sennae (10 mL/kg) for 2 weeks, and then enema of mixture solution of 5% trinitro-benzene-sulfonic acid (100 mg/kg) + 50% ethyl alcohol. Rats of the medication group received gavage of SASP. The catgut-embedment was applied to bilateral "Tianshu"(ST23),"Zusanli"(ST36), "Geshu"(BL17), "Pishu"(BL20), "Shenshu"(BL23) and "Dachangshu"(BL25), once every two weeks, 3 times altogether. The body mass was recorded, and histopathological changes of the colon tissues were observed after H.E. staining. The contents of serum D-lactic acid (D-LA), diamine oxidase (DAO) and protein kinase C (PKC) were detected by ELISA. The expression levels of occludin, claudin-8, cingulin and zonulin mRNAs and proteins and PKC protein of the colon tissues were detected by using quantitative real-time PCR and Western blot, separately. Compared with the control group, the body mass and expression levels of colonic occludin, claudin-8 and cingulin mRNAs and proteins were significantly lower (P<0.01), and the colonic mucosa damage index (CMDI) score, contents of serum D-LA, DAO and PKC, as well as the expression levels of zonulin mRNA and protein and PKC protein were significantly higher in the model group (P<0.01). In comparison with the model group, the body mass, and the expression levels of occludin, claudin-8 and cingulin mRNAs and proteins were significantly higher (P<0.05, P<0.01), whereas the CMDI score, expression levels of zonulin mRNA and protein and PKC protein were remarkably lower in both the medication group and acupoint embedding groups (P<0.05,P<0.01). No significant differences were found between the acupoint embedding and medication groups in all the indexes mentioned above (P>0.05). H.E. staining showed markedly swollen, disordered arrangement of intestinal mucosal cells, and hemorrhage with infiltration of inflammatory cells in the colonic tissues after modeling, which was relatively milder in both medication and acupoint embedding groups. Acupoint catgut embedding can reduce colonic tissue injury in UC rats, which may be related to its functions in regulating the expression of intestinal epithelial tight junction proteins and mRNAs and in inhibiting the activation of PKC protein.

Interaction of alcohol with time of eating on markers of circadian dyssynchrony and colon tissue injury

BackgroundAlcohol increases the risk of developing colon cancer (CRC), in part via tissue inflammation and impaired barrier integrity. Circadian dyssynchrony (CD) is an understudied but common lifestyle associated factor that increases the risk of multi-organ tissue injury and number of malignancies including CRC. Our prior studies showed that the shift in light-dark cycle exacerbates barrier dysfunction and colonic inflammation in the setting of alcohol treatment, and increases the risk of CRC. Here we studied the interaction of alcohol with an abnormal eating pattern on markers of CD and colonic barrier integrity. MethodMice were subjected to day (rest-phase = wrong-time WT) or night-time (active-phase = right-time RT) access to food in combination with access to water or 15% alcohol for total duration of 10 weeks. The food and liquid intake was measured. The locomotor activity data was recorded throughout the study, using a beam-break system. Mice were euthanized at two time points (ZT2 and ZT14). Time variation in the expression of the molecular marker of circadian clock (per2 gene) was measured in the central (hypothalamus) and intestinal (colon) tissue. Colonic protein expression of barrier markers (Occludin and Claudin-1) was studied. ResultsNo significant differences were present in the weight gain and alcohol intake among the groups over the study period. We observed an interaction of WT eating with alcohol on behavioral markers of circadian rhythm. Compared to the RT + Water treated animals (“reference group”), combination of WT eating and alcohol consumption (WT + Alcohol) significantly changed the per2 oscillatory pattern, that was different between the colon and hypothalamus, indicative of worsening circadian dyssynchrony. This was associated with an overall impaired expression of barrier integrity markers in the colon. ConclusionsAlcohol induces circadian dyssynchrony which is worsened by abnormal food timing, associated with impaired barrier integrity in the colon. Future studies on the interaction of alcohol and food timing could provide further insights into alcohol associated CRC pathophysiology.

Gliclazide attenuates acetic acid-induced colitis via the modulation of PPARγ, NF-κB and MAPK signaling pathways

Ulcerative Colitis is a universal autoimmune disease with high incidence rates worldwide. It is characterized by the existence of many other concurrent immune-associated ailments, including diabetes. The used strategies for the management of this highly costing and complicated disease face great challenges. Therefore, the urge for new medication with fewer side effects and high efficacy is growing. The peroxisome proliferator-activated receptor-gamma (PPARγ) and nuclear factor Kappa-B (NF-κB) can be considered as crucial targets for the treatment of ulcerative colitis. Several studies reported the antioxidants, anti-inflammatory, and antiapoptotic actions of gliclazide and evaluated its cardioprotective and renoprotective effects. However, its impact on ulcerative colitis has never been investigated. This study delineated the effect of gliclazide administration on ulcerative colitis induced by acetic acid in rats and the underlying molecular mechanisms. Gliclazide (10 mg/kg; p.o) prominently decreased colon tissue injury as assessed by the histopathological analysis as well as myeloperoxidase, and intercellular adhesion molecule-1 levels. Gliclazide significantly alleviated the proinflammatory mediator, IL-6, promoted the anti-inflammatory cytokine, IL-10 and, withheld oxidative stress in the injured colon tissues. The protective effect of gliclazide was mediated through the upregulation of PPARγ and downregulation of NF-κB expression. The diminution of ulcerative colitis was also accompanied by an inhibition of the elevated activity and expression of mitogen-activated protein kinases and caspase-3 as assessed by Western blot and immunohistochemistry, respectively. Our findings spotlight, for the first time, the potential of the antidiabetic agent, gliclazide, to attenuate the experimentally induced ulcerative colitis. Therefore, gliclazide might be a propitious agent for the management of ulcerative colitis in diabetic patients.

PDTC Alleviates Depressive Symptoms and Colon Tissue Injury via Inhibiting NO Overproduction in CUMS Rats.

BackgroundThe accumulated evidence demonstrates that stress plays an important role in the pathogenesis of depression that is associated with intestinal dysfunctions. However, the mechanisms remain unresolved.MethodsA total of 40 male Wistar rats were obtained and randomly divided into four equal-sized group: control, PDTC + chronic and unpredictable mild stress (CUMS), FLX + CUMS, and CUMS. Western blotting and qRT-PCR were used to examine the levels of nitric oxide (NO), nuclear factor kappa beta (NF-κB), inducible nitric oxide synthase (iNOS), and iNOS mRNA in spinal cord L1-2 and colon.Key ResultsChronic and unpredictable mild stress increased the serum CORT level, decreased body weight and sucrose preference, and altered OFT performance, while increased levels of NO, iNOS mRNA, iNOS and NF-κB protein in colon and spinal cord were accompanied by histopathological changes in colon. Pretreatment with an NF-κB inhibitor, pyrrolidine dithiocarbamate (PDTC), reversed these effects. Fluoxetine failed to prevent NO increase in both spinal cord and colon, while the iNOS protein level, although not statistically significantly increased compared to control, was not decreased compared to CUMS. Also, fluoxetine failed to prevent histological changes.ConclusionIn conclusion, the NF-κB/iNOS pathway may be involved in the mechanism of CUMS-induced depressive-like behavior and colon tissue injury.

Melatonin alleviates circadian rhythm disruption exacerbating DSS-induced colitis by inhibiting the distribution of HMGB1 in intestinal tissues

Circadian rhythm disruption (CRD) is regarded as a risk factor for inflammatory bowel disease (IBD), and it was reported to suppress the level of melatonin, which execute anti-inflammatory effects. High mobility group box 1 protein (HMGB1) is a member of the damage-associated molecular pattern (DAMP) family and has been verified as an IBD-associated inflammatory cytokine that mediates the TLR4-NF-κB pathway. However, no exact mechanism has been illustrated among melatonin, disrupted circadian rhythm and inflammatory bowel disease, as well as regarding the effect of melatonin on HMGB1. In the present study, we aimed to explore the role of relationship with HMGB1. CRD aggravated DSS-induced colitis by worsening colonic inflammation and tissue injury, as well as by enhancing HMGB1 translocation, which could be reversed by ethyl pyruvate, an HMGB1 antagonist. Moreover, melatonin treatment attenuated these disorders and the shuttling of HMGB1 in the intestinal epithelial cells (IECs), the effect of which could be partly reversed by the melatonin antagonist luzindole. The protective role of melatonin may be tightly related to the translocation of HMGB1 in IECs. Accordingly, these results suggested that melatonin may be a new therapeutic beneficial option in IBD patients, especially for those with circadian rhythm disruption.

BHLHA15-Positive Secretory Precursor Cells Can Give Rise to Tumors in Intestine and Colon in Mice

The intestinal epithelium is maintained by long-lived intestinal stem cells (ISCs) that reside near the crypt base. Above the ISC zone, there are short-lived progenitors that normally give rise to lineage-specific differentiated cell types but can dedifferentiate into ISCs in certain circumstances. However, the role of epithelial dedifferentiation in cancer development has not been fully elucidated. We performed studies with Bhlha15-CreERT, Lgr5-DTR-GFP, Apcflox/flox, LSL-Notch (IC), and R26-reporter strains of mice. Some mice were given diphtheria toxin to ablate Lgr5-positive cells, were irradiated, or were given 5-fluorouracil, hydroxyurea, doxorubicin, or dextran sodium sulfate to induce intestinal or colonic tissue injury. In intestinal tissues, we analyzed the fate of progeny that expressed Bhlha15. We used microarrays and reverse-transcription PCR to analyze gene expression patterns in healthy and injured intestinal tissues and in tumors. We analyzed gene expression patterns in human colorectal tumors using The Cancer Genome Atlas data set. Bhlha15 identified Paneth cells andshort-lived secretory precursors (including pre-Paneth label-retaining cells) located just above the ISC zone in the intestinal epithelium. Bhlha15+ cells had no plasticity after loss of Lgr5-positive cells or irradiation. However, Bhlha15+ secretory precursors started to supply the enterocyte lineage after doxorubicin-induced epithelial injury in a Notch-dependent manner. Sustained activation of Notch converts Bhlha15+ secretory precursors to long-lived enterocyte progenitors. Administration of doxorubicin and expression of an activated form of Notch resulted in a gene expression pattern associated with enterocyte progenitors, whereas only sustained activation of Notch altered gene expression patterns in Bhlha15+ precursors toward those of ISCs. Bhlha15+ enterocyte progenitors with sustained activation of Notch formed intestinal tumors with serrated features in mice with disruption of Apc. In the colon, Bhlha15 marked secretory precursors that became stem-like, cancer-initiating cells after dextran sodium sulfate-induced injury, via activation of Src and YAP signaling. In analyses of human colorectal tumors, we associated activation of Notch with chromosome instability-type tumors with serrated features in the left colon. In mice, we found that short-lived precursors can undergo permanent reprogramming by activation of Notch and YAP signaling. Thesecells could mediate tumor formation in addition to traditional ISCs.

Berberine inhibits macrophage M1 polarization via AKT1/SOCS1/NF-κB signaling pathway to protect against DSS-induced colitis

Berberine has been reported to have protective effects in colitis treatment. However, the detailed mechanisms remain unclear. Herein, we demonstrated that berberine could protect against dextran sulfate sodium (DSS)-induced colitis in mice by regulating macrophage polarization. In the colitis mouse model, berberine ameliorated DSS-induced colon shortening and colon tissue injury. Moreover, berberine-treated mice showed significant reduction in the disease activity index (DAI), pro-inflammatory cytokines expression and macrophages infiltration compared with the DSS-treated mice. Notably, berberine significantly reduced the percentage of M1 macrophages. In vitro analysis also confirmed the inhibitory effects of berberine on macrophages M1 polarization in RAW267.4 cells. Further investigation showed that berberine promoted AKT1 expression in mRNA and protein level. Silence of AKT1 abolished the inhibitory effect of berberine on macrophages M1 polarization. The berberine-induced AKT1 expression promoted suppressers of cytokine signaling (SOCS1) activation, which inhibited nuclear factor-kappa B (NF-κB) phosphorylation. In addition, we also found that berberine activated AKT1/SOCS1 signaling pathway but inhibited p65 phosphorylation in macrophages in vivo. Therefore, we concluded that berberine played a regulatory role in macrophages M1 polarization in DSS-induced colitis via AKT1/SOCS1/NF-κB signaling pathway. This unexpected property of berberine may provide a potential explanation for its protective effects in colitis treatment.

The Mbd4 DNA glycosylase protects mice from inflammation-driven colon cancer and tissue injury.

Much of the global cancer burden is associated with longstanding inflammation accompanied by release of DNA-damaging reactive oxygen and nitrogen species. Here, we report that the Mbd4 DNA glycosylase is protective in the azoxymethane/dextran sodium sulfate (AOM/DSS) mouse model of inflammation-driven colon cancer. Mbd4 excises T and U from T:G and U:G mismatches caused by deamination of 5-methylcytosine and cytosine. Since the rate of deamination is higher in inflamed tissues, we investigated the role of Mbd4 in inflammation-driven tumorigenesis. In the AOM/DSS assay, Mbd4−/− mice displayed more severe clinical symptoms, decreased survival, and a greater tumor burden than wild-type (WT) controls. The increased tumor burden in Mbd4−/− mice did not arise from impairment of AOM-induced apoptosis in the intestinal crypt. Histopathological analysis indicated that the colonic epithelium of Mbd4−/− mice is more vulnerable than WT to DSS-induced tissue damage. We investigated the role of the Mbd4−/− immune system in AOM/DSS-mediated carcinogenesis by repeating the assay on WT and Mbd4−/− mice transplanted with WT bone marrow. Mbd4−/− mice with WT bone marrow behaved similarly to Mbd4−/− mice. Together, our results indicate that the colonic epithelium of Mbd4−/− mice is more vulnerable to DSS-induced injury, which exacerbates inflammation-driven tissue injury and cancer.

Berberine ameliorates chronic relapsing dextran sulfate sodium-induced colitis in C57BL/6 mice by suppressing Th17 responses

Ulcerative colitis (UC) is an increasingly common condition particularly in developed countries. The lack of satisfactory treatment has fueled the search for alternative therapeutic strategies. In recent studies, berberine, a plant alkaloid with a long history of medicinal use in Chinese medicine, has shown beneficial effects against animal models of acute UC. However, UC usually presents as a chronic condition with frequent relapse in patients. How berberine will act on chronic UC remains unclear. In the present study, we adopted dextran sulfate sodium (DSS)-induced chronic relapsing colitis model to assess the ameliorating activity of berberine. Colitis was induced by two cycles of 2.0% DSS for five days followed by 14days of drinking water plus a third cycle consisting of DSS only for five days. The colitis mice were orally administered 20mg/kg berberine from day 13 onward for 30days and monitored daily. The body weight, stool consistency, and stool bleeding were recorded for determination of the disease activity index (DAI). At the end of treatment, animals were sacrificed and samples were collected and subjected to histological, RT-qPCR, Western blot, and LC–MS analyses. Lymphocytes were isolated from spleens and mesenteric lymph nodes (MLN) and cultured for flow cytometry analysis of IL-17 secretion from CD4+ cells and the Th17 cell differentiation. Results showed that berberine significantly ameliorated the DAI, colon shortening, colon tissue injury, and reduction of colonic expression of tight junction (TJ) protein ZO-1 and occludin of colitis mice. Notably, berberine treatment pronouncedly reduced DSS-upregulated Th17-related cytokine (IL-17 and ROR-γt) mRNAs in the colon. Furthermore, the mRNA expression of IL-6 and IL-23, and the phosphorylation of STAT3 in colon tissues from DSS-treated mice were pronouncedly inhibited by berberine. Moreover, the up-regulation of IL-17 secretion from CD4+ cells of spleens and MLNs caused by DSS were significantly reversed by berberine treatment. Furthermore, Th17 cell differentiation from naive CD4+ cells isolated from above DSS colitis mice were suppressed by berberine in a concentration-dependent manner. In summary, we demonstrated for the first time that berberine reduced the severity of chronic relapsing DSS-induced colitis by suppressing Th17 responses. The demonstration of activity in this mouse model supports the possibility of clinical efficacy of berberine in treating chronic UC.

IL-33 alleviates DSS-induced chronic colitis in C57BL/6 mice colon lamina propria by suppressing Th17 cell response as well as Th1 cell response

Interleukin (IL)-33, a member of the IL-1 cytokine family, is associated with autoimmune diseases including inflammatory bowel diseases (IBD). A few studies on animal models have shown that IL-33 can suppress Th1 cell response and improve Th2 cell response in mesenteric lymph nodes (MLN) and sera. However, there is little data published about the effect of IL-33 on Th17 cell in and Th1/Th2 cell in colon lamina propria. The aim of this study was to investigate the effect of IL-33 on Th17 cell in colon lamina propria of mice with dextran sulfate sodium (DSS) induced chronic colitis. We studied the influence of IL-33 on colonic tissue injury and clinical symptoms of colitis. The T cell subsets were measured by flow cytometry and the production of cytokines secreted by lamina propria lymphocytes (LPL) was measured by Enzyme-Linked Immunosorbent Assay (ELISA) and quantitative real-time PCR. We have found that rIL-33 treatment led to a significant alleviation of DSS induced chronic colitis as evidenced by 1) alleviation of weight loss, DAI, macroscopic changes and histological score; 2) down-regulating the rates and absolute cell numbers of Th17 and Th1 cell in LPL; 3) inducing secretion of lower levels of IFN-γ and IL-17A. It is therefore concluded that IL-33 may play a therapeutic role in DSS-induced chronic colitis in mice by suppressing Th17 response and switching Th1 to Th2 response.

Novaferon ameliorates dextran sulfate sodium-induced colitis and downregulates expression of TNF-α in mice

To explore the effects of novaferon on dextran sulfate sodium (DSS)-induced colitis and expression of TNF-α in mice and to evaluate the efficacy of novaferon on ulcerative colitis and the possible mechanisms. A total of 70 BALB/C mice [weight (20.0±2.0) g, 8-week years old, female, pathogen free] were randomly divided into 7 groups: a normal group, a model group, a mesalazine treatment group, a prednisone treatment group, a low-dose novaferon group, a middle-dose novaferon group and a high-dose novaferon group (10 mice per group). The normal group-mice were given distilled water. The ulcerative colitis model was established by treated the mice with 4% DSS for 7 continuous days. At the 8th day, the mice in the all of drug treatment groups were injected corresponding drugs (i.p.). During the experiment, the general situation, daily weight, stool trait and occult blood were recorded, and the mice were killed on the 14th day. The disease activity index (DAI), colon length, histological scores were assessed. Immunohistochemistry was used to measure the expression of TNF-α in colonic mucosa. 1) The mice treated with DSS solution showed diarrhea, mucous stool and bloody stool, and the DAI score increased gradually. The mesalazine, predinison and nofaferon could ameliorate the general situation of the mice, reduce the DAI and histological scores, and reverse the decrease in the colon length. 2) Compared with the model group, the DAI scores were significantly decreased in the novaferon groups (at low, middle or high dose), the mesalazine group or the prednisone group (all P<0.01), but there was no difference among the mesalazine group, the prednisone group and the low-dose novaferon group (all P>0.05). The efficacy of novaferon in the middle-dose group and the high-dose group are better than that in the mesalazine group, the prednisone group and the low-dose novaferon group (all P<0.01). The efficacy of novaferon showed a dose-dependent manner. 3) The injury of colonic mucosa was relatively mild in the novaferon groups (at low-dose, middle-dose or high-dose), the mesalazine group and the prednisone group, and there were partial glands and less inflammatory cells. Compared with the model group, there was statistics difference (all P<0.05). The tissue injury was significantly alleviated, and the DAI score was decreased in the high-dose novaferon group compared the middle-dose novaferon group (P<0.05), but there was no significant difference between the low-dose novaferon group and the middle-dose novaferon group or between the mesalazine group and the prednisone group (both P>0.05). 4) The TNF-α expression was significantly down-regulated in the novaferon groups (at low-dose, middle-dose or high-dose), the mesalazine group and the prednisone group compared with model group (all P<0.01); but there was no significant difference between the mesalazine group and the prednisone group (P>0.05); the decrease of TNF-α expression by novaferon displayed a dose-dependent manner. Compared with the mesalazine group or the prednisone group, the TNF-α expression in novaferon groups at all dosages was dramatically reduced (all P<0.01). Novaferon can improve the DAI scores and colonic tissue injury in ulcerative colitis induced by DSS in mice, and down-regulate the TNF-α expression in dose-dependent manner.

Anti-inflammatory effects of orally administered glucosamine oligomer in an experimental model of inflammatory bowel disease

Anti-inflammatory effects of oral administration of the glucosamine oligomers (chito-oligosaccharides: COS) were evaluated in an experimental model of inflammatory bowel disease (IBD). Oral administration of COS improved shortening of colon length and tissue injury (as assessed by histology) in mice. Oral administration of COS inhibited inflammation in the colonic mucosa by suppression of myeloperoxidase activation in inflammatory cells, as well as activation of nuclear factor-kappa B, cyclooxygenase-2, and inducible nitric oxide synthase. Oral administration of COS also reduced serum levels of pro-inflammatory cytokines (tumor necrosis factor-α and interleukin-6). Moreover, it prolonged survival time in mice. These data suggest that COS have anti-inflammatory effects in an experimental model of IBD, and could be new functional foods for IBD patients.

P40phoxExpression Regulates Neutrophil Recruitment and Function during the Resolution Phase of Intestinal Inflammation

NADPH oxidase is a multisubunit complex that assembles during phagocytosis to generate reactive oxygen species. Several components of this complex have been implicated in chronic granulomatous disease and Crohn's disease, highlighting the importance of reactive oxygen species in regulating host immune response. In this study, we use genetically deficient mice to elucidate how p40(phox), one subunit of the NADPH oxidase complex, functions during intestinal inflammation. We show that p40(phox) deficiency enhances inflammation in both dextran sulfate sodium-induced and innate immune-mediated murine colitis models. This inflammation is characterized by severe colonic tissue injury, increased proinflammatory cytokines, and increased neutrophil recruitment. We demonstrate that neutrophils are essential during the recovery phase of intestinal inflammation and that p40(phox) expression is necessary for this restitution. Lastly, using an integrative bioinformatic approach, we show that p40(phox) deficiency leads to upregulation of chemokine receptor 1 and downregulation of enzymes involved in glycan modifications, including fucosyltransferases and sialyltransferases, during inflammation. We propose that p40(phox) deficiency enhances intestinal inflammation through the dysregulation of these two pathways in neutrophils.

Interleukin-33 Ameliorates Experimental Colitis through Promoting Th2/Foxp3+ Regulatory T-Cell Responses in Mice

Crohn's disease (CD) is characterized by the activation of Th1 and Th17 cells and deficiency of regulatory T cells (Tregs), leading to intestine tissue injury and destruction. As a novel cytokine of the interleukin (IL)-1 family, the role and underlying mechanisms of IL-33 in CD remain poorly understood. Here, we assess the effects and mechanisms of IL-33 on the trinitrobenzene sulfonic acid (TNBS)-induced experimental colitis that mimics human CD. We found that IL-33 levels were increased in the TNBS-treated mice, whereas recombinant IL-33 (rIL-33) administration substantially ameliorated TNBS-mediated colonic tissue injury and clinical symptoms of colitis. The protective effect of rIL-33 was partly associated with the markedly increased induction of Th2-type cytokines. Importantly, rIL-33 treatment resulted in prominently upregulated Foxp3 expression in the TNBS-treated mice, and depletion of Tregs significantly abrogated the impact of IL-33 on reducing the development of colitis. Notably, the level of CD103⁺ dendritic cells (DCs), which promotes development of Tregs, is also increased in mesenteric lymph node and lamina propria of rIL-33-treated mice. The impact of rIL-33 on CD103⁺ DC induction was the result of indirectly upregulating intestine epithelial cells that produce thymic stromal lymphopoietin and retinoic acid but do not directly act on DCs. In conclusion, our data provide clear evidence that IL-33 plays a protective role in TNBS-induced colitis, which is closely related to a Th1-to-Th2/Treg switch. Thus, IL-33 is a promising candidate for the development of new treatments for CD.

Moxibustion activates mast cell degranulation at the ST25 in rats with colitis

To investigate the effects of moxibustion on the morphology and function of mast cells (MC) at Tianshu (ST25) in rats with trinitro-benzene-sulfonic acid (TNBS)-induced colitis. A total of 53 male Sprague-Dawley rats were randomly divided into a normal group and experimental group. In the experimental group, a rat model of TNBS-induced colitis was established, and the rats were then randomly divided into a model group, moxibustion group, moxibustion plus disodium cromoglycate (M + DC) group and moxibustion plus normal saline (M + NS) group. Rats in the moxibustion group received suspended moxibustion at bilateral ST25 for 10 min, once a day for 7 d. Rats in the M + DC and M + NS groups were pretreated with disodium cromoglycate and normal saline at bilateral ST25, respectively, and were then concurrently subjected to the same treatment as rats in the moxibustion group. The hematoxylin-eosin staining method was used to observe histology of the colon and the toluidine blue-improved method was used to observe mast cells at ST25 acupoint areas. An improvement in colonic injury in the moxibustion group was observed and the degranulation ratio of MC at ST25 acupoint was markedly higher in the moxibustion group than in the model group (45.91 ± 11.41 vs 32.58 ± 8.28, P < 0.05). After inhibition of degranulation of MC at ST25 by disodium cromoglycate, no improvement in colon tissue injury was observed. Moxibustion exerted its effect on healing impaired colonic mucosa in rats with TNBS-induced colitis by increasing the degranulation ratio of local MC, but had little effect on the morphology of MC at ST25 acupoint.

Recent aspects of the anti-inflammatory actions of glucosamine

Glucosamine, a naturally occurring amino monosaccharide, is present in the connective and cartilage tissues as a component of glycosaminoglycans. Thus, glucosamine has been widely used to treat osteoarthritis, a joint disease characterized by cartilage degeneration, in humans. In addition, glucosamine is expected to exert an anti-inflammatory action, since glucosamine suppresses inflammatory cell activation. To further extend the anti-inflammatory actions of glucosamine, we investigated the effects of glucosamine on synovial cells, endothelial cells and intestinal epithelial cells using in vitro and in vivo systems. Firstly, glucosamine suppressed the IL-1β-induced activation of synovial cells in vitro. Furthermore, glucosamine administration repressed synovial cell hyperplasia, cartilage destruction and inflammatory cell infiltration in rat adjuvant arthritis. Secondary, glucosamine suppressed the TNF-α-induced activation of intestinal epithelial cell HT-29 in vitro. In addition, glucosamine administration improved the clinical symptoms, and colonic inflammation and tissue injury in dextran sulfate sodium-induced colitis in rats. Finally, glucosamine suppressed the TNF-α-induced activation of endothelial cells in vitro. Moreover, glucosamine administration repressed the formation of atherosclerotic lesion and infiltration of inflammatory cells into the lesion in spontaneously hyperlipidemic mice B6 KOR Apo shl. Together these observations support the idea that glucosamine can function as not only a chondroprotective agent but also an anti-inflammatory molecule in the body.

Vitamin C modulates oxidative stress-induced colitis in rats

Free radicals are an important factor in the etiopathogenesis of colitis and may increase oxidative damage. The antioxidant vitamin C efficiently scavenges free oxygen radicals. The present study aimed to investigate the probable protective effects of vitamin C on oxidative injury in rats in which colitis was experimentally induced with acetic acid. Materials and methods: This study was conducted with rats for a period of 7 days. Group 1 intrarectally received a placebo (0.9% NaCl) and group 2 intrarectally received 2 mL of 5% acetic acid (AA) and the placebo. Group 3 intrarectally received 2 mL of 5% AA and vitamin C (100 mg/kg of body weight) via gastric gavage. Myeloperoxidase (MPO), catalase (CAT), prolidase (PRS), and arylesterase (ARE) activity, and total thiol (T-SH), total antioxidant capacity (TAC), total oxidant status (TOS), lipid hydroperoxide (LOOH), and oxidative stress index (OSI) values were analyzed in blood and intestinal samples. Results: While CAT and PRS activity, and plasma TOS, LOOH, and OSI increased following the administration of AA, TAC decreased. TAC increased, whereas LOOH and OSI decreased in response to vitamin C treatment. While MPO and CAT activity, and TOS, LOOH, and OSI values in the colon increased in response to AA treatment, PRS, ARE, T-SH, and TAC decreased. TAC increased in response to vitamin C, whereas MPO, PRS and ARE activity, and TOS, LOOH, and OSI values decreased. While histopathologic colonic injury scores increased (P < 0.001) in response to AA, they decreased in response to vitamin C. Conclusion: Histopathological damage scores, MPO, TOS, LOOH, and OSI decreased significantly in response to vitamin C treatment, whereas TAC increased. Based on these results, we think that vitamin C might play an important role in preventing oxidative stress and colonic tissue injury produced by acetic acid.