Maresin 1 alleviates dextran sulfate sodium-induced ulcerative colitis by regulating NRF2 and TLR4/NF-kB signaling pathway

ObjectiveUlcerative colitis (UC) is one of the most common gastrointestinal diseases, characterized as a chronic, relapsing inflammation that causes damage to the colonic mucosa. Maresin 1 (MaR1), a specialized proresolving mediator, has powerful anti-inflammatory activity that prevents the occurrence of various inflammatory diseases. The aim of this study was to explore the role and potential mechanism of MaR1 in DSS-induced ulcerative colitis.MethodsIn the present study, we established dextran sulfate sodium (DSS)-induced ulcerative colitis rat model in vivo. Rats with colitis received tail vein injection of MaR1, with or without intraperitoneal injection of ML385. The changes of body weight, colon length, disease activity index (DAI), colonic histopathology, inflammatory cytokines, the activity of myeloperoxidase (MPO) and reactive oxygen species (ROS), and infiltration of macrophages expressing F4/80 were analyzed for the evaluation of colitis severity. In addition, protein expressions were detected using western blot.ResultsMaR1 significantly reduced inflammatory cytokines production, and restored body weight, DAI and colonic histopathology. Besides, MaR1 improved the expression of tight junction (TJ) proteins and reduced the infiltration of neutrophil and macrophages, as well as a decreased activity of MPO and ROS. Meanwhile, MaR1 activated Nrf2 signaling and decreased toll-like receptor 4(TLR4)/nuclear factor-κB(NF-κB) activation. Furthermore, ML385, an inhibitor of Nrf2, significantly reversed the protective effect of MaR1.ConclusionMaR1 play a protective role in DSS-induced colitis by activating Nrf2 signaling and inactivating Nrf2-mediated TLR4/NF-κB signaling pathway, which mediate proinflammatory mediators and intestinal TJ proteins in rats, providing novel insights into the therapeutic strategy of colitis.     

Anti‐inflammatory effect of enzymatic hydrolysate of corn gluten in an experimental model of colitis

Objectives Intestinal bacteria are thought to be involved in the initiation and perpetuation of inflammatory bowel diseases. Prebiotics (non‐digestable dietary carbohydrate) have beneficial properties that alter the intestinal flora and contain glutamine‐rich protein. Glutamine significantly decreases indices of inflammation. In this study, an enzymatic hydrolysate of corn gluten (EHCG) was administered by gavage to Sprague‐Dawley rats fed an elemental diet to determine whether EHCG can ameliorate experi‐ mental colitis. Methods Colitis was induced by intrarectal administration of 2,4,6‐trinitrobenzene sulfonic acid after 10 days' daily oral administration of EHCG at 100 and 300 mg/kg. Macroscopic damage was assessed using a scoring system. The mucosa homogenate was sonicated and myeloperoxidase activity and histamine levels measured. Key findings Treatment with EHCG significantly decreased the severity of injury and reduced myeloperoxidase activity and histamine levels in the distal colon mucosa. Conclusions EHCG may have therapeutic benefit as a supplement in enteral nutrition for patients with inflammatory bowel diseases.     

Kolaviron,a Natural Antioxidant and Anti‐Inflammatory Phytochemical Prevents Dextran Sulphate Sodium‐Induced Colitis in Rats

The beneficial effects of kolaviron, a natural biflavonoid from the seeds of Garcinia kola, have been attributed mainly to its antioxidant and anti‐inflammatory effects. This study investigated these effects on dextran sulphate sodium (DSS)‐induced ulcerative colitis in rats. Sulfasalazine served as standard reference in this study. Kolaviron and sulfasalazine were separately co‐administered orally at 200 mg/kg and 500 mg/kg, respectively, to dextran sulphate sodium‐exposed rats for 5 days. The result indicated that kolaviron or sulfasalazine significantly prevented DSS‐induced body weight loss as well as the incidence of diarrhoea and bleeding in DSS‐exposed rats. Kolaviron suppressed the DSS‐mediated increase in colonic nitric oxide concentration and myeloperoxidase activity and significantly prevented the increase in inflammatory mediators, interleukin‐1β and tumour necrosis factor alpha, in the colon of DSS‐treated rats. The significant depletion in colonic antioxidant status in rats exposed to DSS alone was evident by marked reduction in colonic catalase and glutathione S‐transferase activities as well as glutathione content, leading to elevated hydrogen peroxide and lipid peroxidation levels. Histopathologically, DSS alone resulted in severe epithelial erosion, total absence of goblet cells, destruction of the crypts, necrotic and distorted glands, accompanied by marked cellular mononuclear cells infiltration. However, administration of kolaviron and sulfasalazine ameliorated DSS‐induced colitis by increasing the antioxidant status decreased hydrogen peroxide and lipid peroxidation levels and attenuated the adverse effect of DSS on colon architecture. In conclusion, the anti‐colitis effect of kolaviron is related to its intrinsic anti‐inflammatory and anti‐oxidative properties.     

Rhapontin ameliorates colonic epithelial dysfunction in experimental colitis through SIRT1 signaling

Rhapontin (3, 3′, 5-trihydroxy-4′-methoxystilbene-3-O-glucoside) has anti-thrombotic, anti-allergic and anti-diabetic activities. This study aimed to assess the protective effects of rhapontin on intestinal damage in vivo and in vitro. In a dextran sodium sulfate (DSS)-induced mouse model, oral administration of rhapontin (100 mg/kg) significantly attenuated colonic pathological damage and remarkably inhibited infiltration by inflammatory cells, myeloperoxidase (MPO) activity, NLRP3 inflammasome activation and SIRT1 expression in the colon. Moreover, rhapontin prevented DSS-induced impairment in the colon epithelium barrier by increasing the expression of tight junction proteins, such as zonula occludens-1(ZO-1) and occludin, and reduced apoptosis-associated protein (cyt-c, the ratio of bcl-2/bax and cleaved-capase9) expression in the colon. The in vitro results showed that rhapontin significantly reduced NLRP3 inflammasome activation and cleaved caspase-1 expression as well as lowered IL-1β secretion in LPS-stimulated human-THP-1-derived macrophages. Further study revealed that compound EX257 (an SIRT1 inhibitor) blocked the inhibitory effects of rhapontin on NLRP3-dependent caspase-1 activation and IL-β production in activated macrophages. In addition, in TNF-α-stimulated intestinal epithelial NCM460 cells, rhapontin significantly increased the expressions of occludin and ZO-1 and notably reduced the ratio of bcl-2/bax and cleaved-capase9 expression through SRIT1 signaling. In sum, the protective effect of rhapontin is from blocking the NLRP3 priming cascade reaction and is dependent on SIRT1 activation. Our findings demonstrate that rhapontin might be a potential agent for the treatment of colitis by targeting SIRT1.     

Anti‐Inflammatory Effect of Erythropoietin in the TNBS‐induced Colitis

Erythropoietin is a potent stimulator of erythroid progenitor cells, which is able to inhibit NF‐kB activation, due to its pleiotropic properties, thus promoting an anti‐inflammatory effect. As inflammatory bowel disease is a chronic disease with reduced quality of life, and the current pharmacotherapy only induces or maintains the patient in remission, there is a crucial need of new pharmacological approaches. The main objective of this study was to evaluate the effect of erythropoietin in the TNBS‐induced colitis model in mice with a normal intestinal flora. Mice with TNBS‐induced colitis were treated with a daily dose of erythropoietin at 500 IU/kg bw/day and 1000 IU/Kg bw/day IP during 4 days. As to clinical symptoms/signs, erythropoietin attenuated the decreased body‐weight and reduced diarrhoea and oedema of the anus registered in the non‐treated mice group in a dose‐dependent manner. The anti‐inflammatory properties of erythropoietin in the TNBS‐induced colitis were confirmed by suppression of pro‐inflammatory mediators, such as TNF‐α, IL‐1β and MPO, as well as a significant increase in the anti‐inflammatory cytokine, IL‐10, was promoted. These treated mice also presented a reduction in haemoglobin faecal and ALP, suggesting a beneficial effect of erythropoietin in the haemorrhagic focus and destruction of the enterocyte associated with the colon injury induced by TNBS, respectively. The histopathological score was reduced after treatment with erythropoietin, decreasing the severity and extension of the colitis. Furthermore, renal and hepatic biomarkers, as well as haematocrit concentration, remained stabilized after treatment. In conclusion, erythropoietin reduces the inflammatory response associated with TNBS‐induced colitis in mice.     

Protective effect of curcumin,a Curcuma longa constituent,in early colonic inflammation in rats

Curcumin, a polyphenol derived from the plant, Curcuma longa, has a variety of pharmacological effects, including chemotherapeutic, anti‐inflammatory, antiangiogenic, and antioxidant activities. To gain a better understanding of the effects and mechanisms of action of curcumin on the acute injury caused by intra‐colonic administration of acetic acid (AA) in rats, inflammation was assessed by histology and myeloperoxidase activity (MPO; an index of neutrophil infiltration in the mucosa); Th1 and Th2 cytokine production; histological and histochemical analysis of the lesions; nitrite production in colon mucosa; and the expression of iNOS, COX‐1 and ‐2 using Western blotting and inmmunohistochemistry. We also studied the involvement of the p38 MAPK/JNK signalling pathway in the protective effect of curcumin in acute colonic inflammation. Curcumin (50–100 mg/kg/day) reduced the degree of colonic injury, the index of neutrophil infiltration and Th1 cytokine secretion, and increased IL‐10 production, reduced colonic levels of nitrites, and reduced COX‐2 and iNOS overexpression. A reduction in the activation of p38 and JNK MAPKs was also observed. Thus, we show that the widely used food additive, curcumin reduced the development of AA‐induced colitis and alleviated the inflammatory response. Inhibition of MAPK signalling by curcumin could explain the changes on the cytokine Th1/Th2 profile, the reduction of COX‐2 and iNOS signaling, as well as the decreased nitrite production in colonic mucosa, suggesting that curcumin may be useful in the treatment of ulcerative colitis. Drug Dev Res, 2009. © 2009 Wiley‐Liss, Inc.     

Development of an XBP1 agonist,HLJ2,as a potential therapeutic agent for ulcerative colitis

OBJECTIVE To identify the valid targets and new drugs of ulcerative colitis(UC),a recurrent and intractable inflammatory bowel disease.METHODS and RESULTS In an in vivo mouse model of DSS-induced colitis,HLJ2 decreased weight loss,colon contracture,disease activity index(DAI),colon mucosa damage index(CMDI)and histopathological index(HI).HLJ2 also decreased myeloperoxidase(MPO)activity and reduced production of the inflammatory cytokines TNF-α,IL~(-1)β,and IL-6.HLJ2 improved intestinal mucosa damage induced by dextran sodium sulfate(DSS)and increased the expression of ZO-1 and claudin-1.Fecal 16s rRNA high-throughput sequencing demonstrated a significant improvement in UC intestinal dysbacteriosis in mice treated with HLJ2,including increased abundance of probiotics such as Lachnospiraceae,Prevotellaceae,and Lactobacillaceae.At the same time there was a reduction in the abundance of pathogenic or conditional pathogenic microorganisms such as Bacteroidaceae,Porphyromonadaceae,Deferribacteraceae,and Pseudomonadaceae in HLJ2-treated mice compared with untreated mice.CONCLUSION Our results demonstrated that the XBP1 agonist HLJ2 inhibits inflammation,regulates the intestinal flora,and protects the intestinal mucosa.It is thus a potential therapeutic agent for ulcerative colitis.     

N-methyl-d-aspartate receptor antagonist therapy suppresses colon motility and inflammatory activation six days after the onset of experimental colitis in rats

We set out to investigate the time-dependent colon motility and inflammatory changes in a rodent model of 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis in order to estimate the efficacy of N-methyl-d-aspartate (NMDA) receptor antagonist therapy administered 6 day after the acute inflammatory event. Anaesthetized Sprague-Dawley rats were randomized to control (n=6) or colitis groups (n=18). The endogenous NMDA receptor antagonist kynurenic acid (n=6) or the synthetic analog SZR-72 (n=6) was administered 6 day after TNBS induction. Large bowel motility parameters, macrohaemodynamics and serosal microcirculatory changes were recorded; the severity of colonic damage was monitored by using in vivo confocal laser endomicroscopy. Nitrite/nitrate and nitrotyrosine levels, and xanthine oxidoreductase and myeloperoxidase activities were determined on colon biopsies; plasma levels of TNF-α and IL-6 were compared with those under control and 1-day colitis (n=6) conditions. TNBS induction elevated the tissue inflammatory enzyme activities, proinflammatory cytokine release, and nitrite/nitrate and nitrotyrosine formation. The microscopic vascular and mucosal lesions were accompanied by significant increases in serosal microcirculation and frequent intestinal movements 6 day after colitis. The NMDA receptor antagonist treatments significantly decreased the signs of inflammatory activation and the levels of nitric oxide end-products, normalized the microcirculation and the rate of bowel movements in both NMDA receptor antagonist-treated colitis groups. Blockade of the enteric NMDA receptors 6 day after colitis induction concurrently influenced NO production-linked nitrosative stress and colon dysmotility and may therefore offer a possibility via which to inhibit the progression of inflammatory changes in the later phase of TNBS colitis.     

Autophagy induction by rapamycin ameliorates experimental colitis and improves intestinal epithelial barrier function in IL-10 knockout mice

BackgroundAn impairment of the intestinal barrier function is one of the major characteristics of Crohn’s disease (CD). This study aimed to evaluate the impact of autophagy induction by rapamycin on the intestinal epithelial barrier function in CD model mice.MethodsIL-10 knockout (IL-10 KO) mice were used as the human CD models in this study. All the mice were randomly assigned into four groups, (a) wild-type (WT) group; (b) IL-10 KO group; (c) IL-10 KO + rapamycin group and (d) IL-10 KO + 3-methyladenine (3-MA), containing 6 mice in each group. The disease activity index (DAI), histology, pro-inflammatory cytokines and chemotactic factors in colon tissues, intestinal and colonic permeability, distributions and expressions of tight junction (TJ) proteins, epithelial apoptosis of mice in four groups were evaluated and compared.ResultsAutophagy induction by rapamycin treatment ameliorated DAI and histological colitis, decreased pro-inflammatory cytokines (TNF-α, IFN-γ and IL-17) and chemotactic factors (CXCL-1 and CXCL-2), decreased intestinal and colonic permeability, improved the distribution and expression of TJ proteins in IL-10 KO mice.ConclusionAutophagy induction by rapamycin significantly improved intestinal barrier function and protected IL-10 KO mice from the experimental chronic colitis.     

The adenosine A3 receptor agonist,N6-(3-iodobenzyl)-adenosine-5'-N-methyluronamide,is protective in two murine models of colitis

This study evaluated the effects of the adenosine A(3) receptor agonist, N(6)-(3-iodobenzyl)-adenosine-5'-N-methyluronamide (IB-MECA), in two murine models of colitis, the dextran sodium sulphate-induced colitis and the spontaneous colitis found in interleukin-10 gene deficient mice. IB-MECA was given orally twice a day at a dose of either 1 or 3 mg/kg/day. Evaluation of colon damage and inflammation was determined grossly (body weight, rectal bleeding) and biochemically (colon levels of myeloperoxidase, malondialdehyde, chemokines and cytokines). There was significantly increased inflammatory cell infiltration into the colon associated with an increase in colon levels of cytokines and chemokines; with subsequent free radical related damage in both dextran sodium sulphate-induced colitis and 10-week-old interleukin-10(-/-) mice. IB-MECA protected in both models against the colitis induced inflammatory cell infiltration and damage and attenuated the increases in colon inflammatory cytokine and chemokine levels. Thus activation of the adenosine A(3) receptor is effective in protecting against colitis.     

Effect of the macrolide antibacterial drug, tylosin, on TNBS-induced colitis in the rat

Bacterial antigens, such as intestinal microflora, are known to play a role in the pathogenesis of human inflammatory bowel disease (IBD). Tylosin, a macrolide antimicrobial agent, has proven to be effective in cat and dog chronic colitis, but the reasons underlying this efficacy are still unclear. In the present study we evaluated the effects of tylosin on 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis in the rat, in comparison with the antibacterial drug metronidazole and the corticosteroid budesonide. Colitis was induced by a single intrarectal administration of 10 mg TNBS under light ether anesthesia. Tylosin (20 mg/kg twice a day), metronidazole (160 mg/kg twice a day) and budesonide (500 microg/kg once a day) were given orally for up to 6 days to separate groups of rats. The animals were sacrificed after 6 days and colonic lesions evaluated (colon weight, macroscopic and histologic damage, myeloperoxidase activity). Tylosin and metronidazole significantly lowered macroscopic lesion score, reduced colon weight, the severity of histologic lesions and myeloperoxidase activity; budesonide did not significantly change the parameters of colonic inflammation. These data indicate a protective effect of tylosin against intestinal inflammation, suggesting a major role for bacteria, anaerobes in particular, in the development of TNBS-induced mucosal damage.     

Novel formulation of solid lipid microparticles of curcumin for anti‐angiogenic and anti‐inflammatory activity for optimization of therapy of inflammatory bowel disease

Objectives This project was undertaken with a view to optimize the treatment of inflammatory bowel disease through a novel drug delivery approach for localized treatment in the colon. Curcumin has poor aqueous solubility, poor stability in the gastrointestinal tract and poor bioavailability. The purpose of the study was to prepare and evaluate the anti‐inflammatory activity of solid lipid microparticles (SLMs) of curcumin for the treatment of inflammatory bowel disease in a colitis‐induced rat model by a colon‐specific delivery approach. Methods We have developed a novel formulation approach for treating experimental colitis in the rat model. SLMs of curcumin were prepared with various lipids, such as palmitic acid, stearic acid and soya lecithin, with an optimized percentage of poloxamer 188. The SLMs of curcumin were characterized for particle size, drug content, drug entrapment, in‐vitro release, surface morphology and infrared, differential scanning calorimetry and X‐ray studies. The colonic delivery system of SLM formulations of curcumin were further investigated for their anti‐angiogenic and anti‐inflammatory activity using chick embryo and rat colitis models. Key findings Particle size, drug content, drug entrapment and in‐vitro release studies showed that formulation F4 containing one part stearic acid and 0.5% surfactant had the smallest diameter of 108 μm, 79.24% entrapment and exhibited excellent in‐vitro release characteristics when compared with other formulations and pure curcumin. SLMs of curcumin (F4) proved to be a potent angio‐inhibitory compound, as demonstrated by inhibition of angiogenesis in the chorioallantoic membrane assay. Rats treated with curcumin and its SLM complex showed a faster weight gain compared with dextran sulfate solution (DSS) control rats. The increase in whole colon length appeared to be significantly greater in SLM‐treated rats when compared with pure curcumin and DSS control rats. An additional finding in the DSS‐treated rats was chronic cell infiltration with predominance of eosinophils. Decreased mast cell numbers in the mucosa of the colon of SLMs of curcumin and pure curcumin‐treated rats was observed. Conclusions The degree of colitis caused by administration of DSS was significantly attenuated by colonic delivery of SLMs of curcumin. Being a nontoxic natural dietary product, curcumin could be useful in the therapeutic strategy for inflammatory bowel disease patients.     

Gallic acid suppresses inflammation in dextran sodium sulfate-induced colitis in mice: Possible mechanisms

Inflammatory bowel diseases (IBD) encompass at least two forms of intestinal inflammation: Crohn's disease and ulcerative colitis (UC). Both conditions are chronic and inflammatory disorders in the gastrointestinal tract, with an increasing prevalence being associated with the industrialization of nations and in developing countries. Patients with these disorders are 10 to 20 times more likely to develop cancer of the colon. The aim of this study was to characterize the effects of a naturally occurring polyphenol, gallic acid (GA), in an experimental murine model of UC. A significant blunting of weight loss and clinical symptoms was observed in dextran sodium sulfate (DSS)-exposed, GA-treated mice compared with control mice. This effect was associated with a remarkable amelioration of the disruption of the colonic architecture, a significant reduction in colonic myeloperoxidase (MPO) activity, and a decrease in the expression of inflammatory mediators, such as inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, and pro-inflammatory cytokines. In addition, GA reduced the activation and nuclear accumulation of p-STAT3^Y705, preventing the degradation of the inhibitory protein IκB and inhibiting of the nuclear translocation of p65-NF-κB in colonic mucosa. These findings suggest that GA exerts potentially clinically useful anti-inflammatory effects mediated through the suppression of p65-NF-κB and IL-6/p-STAT3^Y705 activation.     

Anti-inflammatory effect of glucose-lysine Maillard reaction products on intestinal inflammation model in vivo

Inflammatory bowel diseases (IBDs) are chronic disorders that are characterized by intestinal epithelial inflammation and injury. Currently, the most employed therapies are antibiotics and anti-inflammatory drugs; however, the side effects limit long-term effectiveness. We evaluated the impact of glucose-lysine Maillard reaction products (Glc-Lys MRPs) on colitis, induced in rats by an administration of 5% dextran sulfate sodium (DSS) in drinking water. Glc-Lys MRPs ameliorate DSS-induced colitis, as determined by a decrease in disease index activity, colon weight/length ratio, nitric oxide levels in serum, recovery of body weight loss, colon length and serum lysozyme levels. Furthermore, Glc-Lys MRPs increase the glutathione content and the activity of glutathione peroxidase, superoxide dismutase and catalase, and inhibit lipid peroxidation and myeloperoxidase activity in colon tissues. In particular, Glc-Lys MRPs suppress the mRNA level of the inflammatory cytokines and nuclear factor-κB in colon tissues. This study suggests the potential of Glc-Lys MRPs in preventing or treating IBDs.     

Heparin and low-molecular-weight heparin (enoxaparin) significantly ameliorate experimental colitis in rats

Background and aims:

The anticoagulants, unfractionated heparin and low‐molecular‐weight heparin, demonstrated anti‐inflammatory effects in animal models and in humans. Because of its dual effects, high‐dose heparin was proposed as a therapeutic modality for ulcerative colitis. We investigated whether a low dose of low‐molecular‐weight heparin—enoxaparin (Clexane, Rhône‐Poulenc Rorer, France)—ameliorates the inflammatory response in two models of experimental colitis.

Methods:

Colitis was induced in rats by intrarectal administration of dinitrobenzene sulphonic acid. Enoxaparin (40, 80 and 200 μg/kg) or unfractionated heparin (100, 200 and 400 U/kg) were administered subcutaneously immediately after the induction of damage. Enoxaparin, 80 μg/kg, was also administered after induction of colitis by intrarectal administration of iodoacetamide. Rats were sacrificed 1, 3 or 7 days after induction of injury. Colonic damage was assessed macroscopically and histologically. Mucosal prostaglandin E₂ generation, myeloperoxidase and nitric oxide synthase activities and tumour necrosis factor‐α levels in blood were determined.

Results:

Enoxaparin and heparin significantly ameliorated the severity of dinitrobenzene sulphonic acid‐ and iodoacetamide‐induced colitis as demonstrated by a decrease in mucosal lesion area, colonic weight and mucosal myeloperoxidase and nitric oxide synthase activities. The dose–response curve had a bell‐shaped configuration: enoxaparin, 80 μg/kg, and unfractionated heparin, 200 U/kg, were the optimal doses.

Conclusions:

Low‐dose enoxaparin and unfractionated heparin ameliorate the severity of experimental colitis. This effect is related to their anti‐inflammatory rather than anticoagulant properties.

     

Hederacoside C ameliorates colitis via restoring impaired intestinal barrier through moderating S100A9/MAPK and neutrophil recruitment inactivation

Hederacoside C (HSC) has attracted much attention as a novel modulator of inflammation, but its anti-inflammatory mechanism remains elusive. In the present study, we investigated how HSC attenuated intestinal inflammation in vivo and in vitro. HSC injection significantly alleviated TNBS-induced colitis by inhibiting pro-inflammatory cytokine production and colonic epithelial cell apoptosis, and partially restored colonic epithelial cell proliferation. The therapeutic effect of HSC injection was comparable to that of oral administration of mesalazine (200 mg·kg⁻¹·d⁻¹, i.g.). In LPS-stimulated human intestinal epithelial Caco-2 cells, pretreatment with HSC (0.1, 1, 10 μM) significantly inhibited activation of MAPK/NF-κB and its downstream signaling pathways. Pretreatment with HSC prevented LPS-induced TLR4 dimerization and MyD88 recruitment in vitro. Quantitative proteomic analysis revealed that HSC injection regulated 18 proteins in the colon samples, mainly clustered in neutrophil degranulation. Among them, S100A9 involved in the degranulation of neutrophils was one of the most significantly down-regulated proteins. HSC suppressed the expression of S100A9 and its downstream genes including TLR4, MAPK, and NF-κB axes in colon. In Caco-2 cells, recombinant S100A9 protein activated the MAPK/NF-κB signaling pathway and induced inflammation, which were ameliorated by pretreatment with HSC. Notably, HSC attenuated neutrophil recruitment and degranulation as well as S100A9 release in vitro and in vivo. In addition, HSC promoted the expression of tight junction proteins and repaired the epithelial barrier via inhibiting S100A9. Our results verify that HSC ameliorates colitis via restoring impaired intestinal barrier through moderating S100A9/MAPK and neutrophil recruitment inactivation, suggesting that HSC is a promising therapeutic candidate for colitis.     

Nafamostat mesilate attenuates colonic inflammation and mast cell infiltration in the experimental colitis

Serine proteases are important in the pathogenesis of intestinal inflammation. Recent studies have shown that nafamostat mesilate (NM) can inhibit the colonic mucosal inflammation induced by TNBS in rats. The aim of this study was to investigate the anti-inflammatory effects of NM on a DSS-induced colitis. Colitis was induced in female BALB/c mice by 5% dextran sulfate sodium (DSS) for 6 days. NM (2 or 20mg/kg body weight) was orally administered once a day for 6 days during treatment of the mice with DSS. The inflammatory response of the colon was assessed 1 week after DSS treatment. NM at a high dose, but not at a low dose significantly decreased disease activity index (DAI) and myeloperoxidase (MPO) induced by DSS. Furthermore, NM (20mg/kg) inhibited the production of tumor necrosis factor (TNF)-α, cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in the colonic tissues treated with DSS. The increase in chymase activity by DSS treatment was also attenuated by the administration of NM (20mg/kg). NM (20mg/kg) significantly decreased the colonic mucosal injury and the infiltrated mast cell number induced by DSS. These results indicate that NM might inhibit the colonic inflammation through inhibition of both chymase activity and mast cell infiltration in colon tissues of DSS-induced colitis.     

Down‐regulation of hepatic CYP3A1 expression in a rat model of indomethacin‐induced small intestinal ulcers

The liver and the small intestine are closely related in the processes of drug absorption, metabolism and excretion via the enterohepatic circulation. Small intestinal ulcers are a serious adverse effect commonly occurring in patients taking nonsteroidal anti‐inflammatory drugs. However, the influence of small intestinal ulcers on drug metabolism has not been established. This study examined the expressional changes of cytochrome P450 (CYP) in the liver using an indomethacin‐induced small intestinal ulcer rat model and in cultured cells. After the administration of indomethacin to rats, ulcers were observed in the small intestine and expression of CYP3A1, the major isoform of hepatic CYP, was significantly down‐regulated in the liver, accompanied by increased expression of inducible nitric oxide synthase, tumor necrosis factor α, interleukin (IL)‐1β and IL‐6, in the small intestine and the liver. The indomethacin‐induced small intestinal ulceration, the increase in inflammatory mediators in the small intestine and the liver, and the down‐regulation of CYP3A1 expression in the liver were inhibited by co‐administration of ampicillin, an antibacterial agent. In the human hepatic HepG2 cell line, IL‐1β, IL‐6 and NOC‐18, an NO donor, caused down‐regulation of CYP3A4, the major isoform of human CYP3A. Thus, this study suggests that after indomethacin treatment small intestinal ulcers cause the down‐regulation of CYP3A1 in the rat liver through an increase in ulcer‐derived inflammatory mediators. Copyright © 2016 John Wiley & Sons, Ltd.