Differences in the effects and action modes of gut commensals against dextran sulfate sodium-induced intestinal inflammation

Inflammatory bowel disease(IBD)is a complex relapsing inflammatory disease in the gut and is driven by complicated host-gut microbiome interactions.Gut commensals have shown different functions in IBD prevention and treatment.To gain a mechanistic understanding of how different commensals affect intestinal inflammation,we compared the protective effects of 6 probiotics(belonging to the genera Akkermansia,Bifidobacterium,Clostridium,and Enterococcus)on dextran sulfate sodium(DSS)-induced colitis in mice with or without gut microbiota.Anti-inflammatory properties(ratio of interleukin(IL)-10 and IL-12)of these strains were also evaluated in an in vitro mesenteric lymph nodes(MLN)co-culture system.Results showed that 4 probiotics(belonging to the species Bifidobacterium breve,Bifidobacterium bifidum,and Enterococcus faecalis)can alleviate colitis in normal mice.The probiotic strains differed in regulating the intestinal microbiota,cytokines(IL-10,IL-1βand interferon(IFN)-γ),and tight junction function(Zonulin-1 and Occludin).By constrast,Akkermansia muciniphila AH39 and Clostridium butyricum FHuNHHMY49T1 were not protective.Interestingly,B.breve JSNJJNM2 with high anti-inflammatory potential in the MLN model could relieve colitis symptoms in antibiotic cocktail(Abx)-treated mice.Meanwhile,E.faecalis FJSWX25M1induced low levels of cytokines in vitro and showed no beneficial effects.Therefore,we provided insight into the clinical application of probiotics in IBD treatment.

Effect of Berberine Chloride on Experimental Murine Colitis Induced by Dextran Sulfate Sodium

Aim To investigate the effect in berberine chloride （BER） on experimental ulcerative colitis in mice. Methods BALB/C mice in 6 groups were allowed to drink either 4% dextran sulfate sodium （DSS） solution or distilled water freely with different doses of BER （15 mg·kg^-1, 45 mg·kg^-1, 150 mg·kg^-1） or sallcylazosulfapyridine （SASP, 520 mg·kg^-1）, and solvent （0. 2 mL/10 mg Wt） once a day for 7 d, respectively. The symptom of ulcerative colitis was evaluated by disease activity index （DAI）. Myeloperoxidase （MPO） and superoxide dismutase （SOD） activities and malondialdehyde （MDA） content were determined by HE staining and immunohistochemistry of expressions of NF-κB p65 and intercellular adhesion molecule 1 （ ICAM-1 ） proteins to observe the damage to colon tissues and possible mechanisms. Results DAI, MPO activity, MDA content and expressions of ICAM-1 and NF-κB p65 were markedly increased, while SOD activity decreased in DSS-treated mice. Treatment of mice with different doses of BER or SASP significantly decreased DAI, MPO activity and MDA content, improved histological changes of colon tissues, blunted the expressions of NF-κB p65 and ICAM-1 proteins, and enhanced SOD activity. Conclusion Berberine chloride has excellent therapeutic effect on ulcerative colitis caused by DSS in mice. The possible mechanism may be related to its antioxidant and anti-inflammatory activities associated with inhibiting the NF-κB activation and ICAM-1 expression.

Dextran sodium sulfate colitis murine model: An indispensable tool for advancing our understanding of inflammatory bowel diseases pathogenesis

Inflammatory bowel diseases(IBD),including Crohn's disease and ulcerative colitis,are complex diseases that result from the chronic dysregulated immune response in the gastrointestinal tract. The exact etiology is not fully understood,but it is accepted that it occurs when an inappropriate aggressive inflammatory respon-se in a genetically susceptible host due to inciting environmental factors occurs. To investigate the path-ogenesis and etiology of human IBD,various animal models of IBD have been developed that provided indispensable insights into the histopathological and morphological changes as well as factors associated with the pathogenesis of IBD and evaluation of therapeutic options in the last few decades. The most widely used experimental model employs dextran sodium sulfate(DSS) to induce epithelial damage. The DSS colitis model in IBD research has advantages over other various chemically induced experimental models due to its rapidity,simplicity,reproducibility and controllability. In this manuscript,we review the newer publicized advances of research in murine colitis models that focus upon the disruption of the barrier function of the intestine,effects of mucin on the development of colitis,alterations found in microbial balance and resultant changes in the metabolome specifically in the DSS colitis murine model and its relation to the pathogenesis of IBD.

Negative impact of bone-marrow-derived mesenchymal stem cells on dextran sulfate sodium-induced colitis

AIM:To investigate the effects of mesenchymal stem cells(MSCs)on dextran sulfate sodium-induced inflammatory bowel disease(IBD).METHODS:C57BL/6 mice were fed 3.5%(g/L)dextran sulfate sodium.On day seven,the mice received intraperitoneal injections of 1×106 MSCs.The survival rate,disease activity index values,and body weight,were monitored daily.On day ten,colon lengths and histopathologic changes were assessed.In addition,immunoregulatory changes following MSC administration were evaluated by determining the levels of effector T cell responses in the spleen and mesenteric lymph nodes,and the expression levels of inflammatory cytokines in homogenized colons.RESULTS:Intraperitoneal administration of MSCs did not prevent development of colitis and did not reduce the clinicopathologic severity of IBD.No significant difference was evident in either survival rate or disease activity index score between the control and MSCtreated group.Day ten-sacrificed mice exhibited no significant difference in either colon length or histopathologic findings.Indeed,the MSC-treated group exhibited elevated levels of interleukin(IL)-6 and transforming growth factor-β,and a reduced level of IL-10,in spleens,mesenteric lymph nodes,and homogenized colons.The IL-17 level was lower in the mesenteric lymph nodes of the MSC-treated group(P=0.0126).In homogenized colons,the IL-17 and tumor necrosis factor-α(P=0.0092)expression levels were also lower in the treated group.CONCLUSION:MSC infusion provided no significanthistopathologic or clinical improvement,thus representing a limited therapeutic approach for IBD.Functional enhancement of MSCs is needed in further study.

Temporal clinical, proteomic, histological and cellular immune responses of dextran sulfate sodium-induced acute colitis

AIM To investigate the temporal clinical, proteomic, histological and cellular immune profiles of dextran sulfate sodium(DSS)-induced acute colitis.METHODS Acute colitis was induced in C57 BL/6 female mice by administration of 1%, 2% or 3% DSS in drinking water for 7 d. Animals were monitored daily for weight loss, stool consistency and blood in the stool, while spleens and colons were harvested on day 8. A time course analysis was performed in mice ingesting 3% DSS, which included colon proteomics through multiplex assay, colon histological scoring by a blinded investigator, and immune response through flow cytometry or immunohistochemistry of the spleen, mesenteric lymph node and colon.RESULTS Progressive worsening of clinical colitis was observed with increasing DSS from 1% to 3%. In mice ingesting 3% DSS, colon shortening and increase in proinflammatory factors starting at day 3 was observed, with increased spleen weights at day 6 and day 8. This coincided with cellular infiltration in the colon from day 2 to day 8, with progressive accumulation of macrophages F4/80^+, T helper CD4^+(Th), T cytotoxic CD8^+(Tcyt) and T regulatory CD25^+(Treg) cells, and progressive changes in colonic pathology including destruction of crypts, loss of goblet cells and depletion of the epithelial barrier. Starting on day 4, mesenteric lymph node and/or spleen presented with lower levels of Treg, Th and Tcyt cells, suggesting an immune cell tropism to the gut. CONCLUSION These results demonstrate that the severity of experimental colitis is dependent on DSS concentration, correlated with clinical, proteomic, histological and cellular immune response on 3% DSS.

Kefir treatment ameliorates dextran sulfate sodium-induced colitis in rats

AIM: To investigate the preventive effect of kefir on colitis induced with dextran sulfate sodium(DSS) in rats.METHODS: Twenty-four male Wistar-albino rats were randomized into four groups: normal control,kefircontrol,colitis,and kefir-colitis groups. Rats in the normal and kefir-control groups were administered tap water as drinking water for 14 d. Rats in the colitis and kefir-colitis groups were administered a 3% DSS solution as drinking water for 8-14 d to induce colitis. Rats in the kefir-control and kefir-colitis groups were administered 5 m L kefir once a day for 14 d while rats in the normal control and colitis group were administered an identical volume of the placebo(skim milk) using an orogastric feeding tube. Clinical colitis was evaluated with reference to the disease activity index(DAI),based on daily weight loss,stool consistency,and presence of bleeding in feces. Rats were sacrificed on the 15 th day,blood specimens were collected,and colon tissues were rapidly removed. Levels of myeloperoxidase(MPO),tumor necrosisfactor(TNF)-α,interleukin(IL)-10,malondialdehyde,and inducible nitric oxide synthase(i NOS) were measured in colon tissue.RESULTS: The DAI was lower in the kefir-colitis group than in the colitis group(on the 3rd and 5th days of colitis induction; P < 0.01). The DAI was also significantly higher in the colitis group between days 2 and 6 of colitis induction when compared to the normal control and kefir-control groups. The DAI was statistically higher only on the 6th day in the kefircolitis group when compared to that in the normal control groups. Increased colon weight and decreased colon length were observed in colitis-induced rats. Mean colon length in the colitis group was significantly shorter than that of the kefir-control group. Kefir treatment significantly decreased histologic colitis scores(P < 0.05). MPO activity in the colitis group was significantly higher than in the kefir-control group(P < 0.05). Kefir treatment significantly reduced the DSS colitis-induced TNF-α increase(P < 0.01). No statistically significant differences were observed among groups for IL-10 and MDA levels. Colon tissue i NOS levels in the colitis group were significantly higher than those in the control and kefir-colitis groups(P < 0.05).CONCLUSION: Kefir reduces the clinical DAI and histologic colitis scores in a DSS-induced colitis model,possibly via reduction of MPO,TNF-α,and i NOS levels.

Protective effects of panax notoginseng saponin on dextran sulfate sodium-induced colitis in rats through phosphoinositide-3-kinase protein kinase B signaling pathway inhibition

BACKGROUND Intestinal inflammation is a common digestive tract disease, which is usually treated with hormone medicines. Hormone medicines are effective to some extent, but long-term use of them may bring about many complications.AIM To explore the protective effects of panax notoginseng saponin(PNS) against dextran sulfate sodium(DSS)-induced intestinal inflammatory injury through phosphoinositide-3-kinase protein kinase B(PI3K/AKT) signaling pathway inhibition in rats.METHODS Colitis rat models were generated via DSS induction, and rats were divided into control(no modeling), DSS, DSS + PNS 50 mg/k, and DSS + PNS 100 mg/kg groups. Then, the intestinal injury, oxidative stress parameters, inflammatory indices, tight junction proteins, apoptosis, macrophage polarization, and TLR4/AKT signaling pathway in colon tissues from rats in each of the groups were detected. The PI3 K/AKT signaling pathway in the colon tissue of rats was blocked using the PI3K/AKT signaling pathway inhibitor, LY294002.RESULTS Compared with rats in the control group, rats in the DSS group showed significantly shortened colon lengths, and significantly increased disease activity indices, oxidative stress reactions and inflammatory indices, as well as significantly decreased expression of tight junction-associated proteins. In addition, the DSS group showed significantly increased apoptotic cell numbers,and showed significantly increased M1 macrophages in spleen and colon tissues.They also showed significantly decreased M2 macrophages in colon tissues, as well as activation of the PI3K/AKT signaling pathway(all P < 0.05). Compared with rats in the DSS group, rats in the DSS + PNS group showed significantly lengthened colon lengths, decreased disease activity indices, and significantly alleviated oxidative stress reactions and inflammatory responses. In addition, this group showed significantly increased expression of tight junction-associated proteins, significantly decreased apoptotic cell numbers, and significantly decreased M1 macrophages in spleen and colon tissues. This group further showed significantly increased M2 macrophages in colon tissues, and significantly suppressed activation of the PI3K/AKT signaling pathway, as well as a dose dependency(all P < 0.05). When the PI3K/AKT signaling pathway was inhibited, the apoptosis rate of colon tissue cells in the DSS + LY294002 group was significantly lower than that of the DSS group(P < 0.05).CONCLUSION PNS can protect rats against DSS-induced intestinal inflammatory injury by inhibiting the PI3K/AKT signaling pathway, and therefore may be potentially used in the future as a drug for colitis.

Involvement of lymphocytes in dextran sulfate sodium-induced experimental colitis

AIM： To investigate the roles of lymphocytes in the development of dextran sulfate sodium-induced colitis. METHODS： Using various doses of dextran sulfate sodium （DSS）, we induced colitis in wild-type B6 control and Rag-1 knockout （H-2b haplotype） mice, and evaluated the colitis in terms of symptomatic and histologic parameters, such as weight loss, survival, severity of diarrhea, shortage of colon length and histological changes. Symptomatic parameters were checked daily and histological changes were scored. RESULTS： Although development of colitis in Rag-1 knockout mice treated with high dose （5%） of DSS was comparable to that in B6 control mice, colitis progression was much more tolerable in Rag-1 knockout mice compared to than in B6 mice treated with low dose （1.5%） DSS. Symptomatic parameters as well as histopathologic changes were improved in Rag-1 knockout mice. CONCLUSION： These results indicate that the presence of lymphoo/tes contributes to colitis progression at low dose of DSS stimulation. Lymphoo/tes may play roles as an aggravating factor in DSS-induced colitis.

Dextran sulfate sodium-induced acute colitis impairs dermal lymphatic function in mice

AIM: To investigate whether dermal lymphatic function and architecture are systemically altered in dextran sulfate sodium(DSS)-induced acute colitis.METHODS: Balb/c mice were administered 4% DSS in lieu of drinking water ad libitum for 7 d and monitored to assess disease activity including body weight, diarrhea severity, and fecal bleeding. Control mice received standard drinking water with no DSS. Changes in mesenteric lymphatics were assessed following oral administration of a fluorescently-labelled fatty acid analogue, while dermal lymphatic function and architecture was longitudinally characterized using dynamic near-infrared fluorescence(NIRF) imaging following intradermal injection of indocyanine green(ICG) at the base of the tail or to the dorsal aspect of the left paw prior to, 4, and 7 d after DSSadministration. We also measured dye clearance rate after injection of Alexa680-bovine serum albumin(BSA). NIRF imaging data was analyzed to reveal lymphatic contractile activity after selecting fixed regions of interest(ROIs) of the same size in fluorescent lymphatic vessels on fluorescence images. The averaged fluorescence intensity within the ROI of each fluorescence image was plotted as a function of imaging time and the lymphatic contraction frequency was computed by assessing the number of fluorescent pulses arriving at a ROI. RESULTS: Mice treated with DSS developed acute inflammation with clinical symptoms of loss of body weight, loose feces/watery diarrhea, and fecal blood, all of which were aggravated as disease progressed to 7 d. Histological examination of colons of DSS-treated mice confirmed acute inflammation, characterized by segmental to complete loss of colonic mucosa with an associated chronic inflammatory cell infiltrate that extended into the deeper layers of the wall of the colon, compared to control mice. In situ intravital imaging revealed that mice with acute colitis showed significantly fewer fluorescent mesenteric lymphatic vessels, indicating impaired uptake of a lipid tracer within mesenteric lymphatics. Our in vivo NIRF imaging data demonstrated dilated dermal lymphatic vessels, which were confirmed by immunohistochemical staining of lymphatic vessels, and significantly reduced lymphatic contractile function in the skin of mice with DSS-induced acute colitis. Quantification of the fluorescent intensity remaining in the depot as a function of time showed that there was significantly higher Alexa680-BSA fluorescence in mice with DSSinduced acute colitis compared to pre-treatment with DSS, indicative of impaired lymphatic drainage.CONCLUSION: The lymphatics are locally and systemically altered in acute colitis, and functional NIRF imaging is useful for noninvasively monitoring systemic lymphatic changes during inflammation.

Attenuation of dextran sodium sulphate induced colitis in matrix metalloproteinase-9 deficient mice

AIM: To study whether matrix metalloproteinase-9 (MMP-9) is a key factor in epithelial damage in the dextran sodium sulphate (DSS) model of colitis in mice.METHODS: MMP-9-deficient and wild-type (wt) mice were given 5% DSS in drinking water for 5 d followed by recovery up to 7 d. On d 5 and 12 after induction of colitis, gelatinases, MMP-2 and MMP-9, were measured in homogenates of colonic tissue by zymography and Western blot, whereas tissue inhibitor of metalloproteinases (TIMPs) were measured by reverse zymography. The gelatinolytic activity was also determined in supernatants of polymorphonuclear leukocytes (PMN) isolated from mice blood. Moreover, intestinal epithelial cells were stimulated with TNF-α to study whether these cells were able to produce MMPs. Finally, colonic mucosal lesions were measured by microscopic examination. RESULTS: On d 5 of colitis, the activity of MMP-9 was increased in homogenates of colonic tissues (0.24 ± 0.1 vs 21.3 ± 6.4, P < 0.05) and PMN from peripheral blood in wt (0.5 ± 0.1 vs 10.4 ± 0.7, P < 0.05), but not in MMP-9-deficient animals. The MMP-9 activity was also up-regulated by TNF-α in epithelial intestinal cells (2.5 ± 0.5 vs 14.7 ± 3.0, P < 0.05). Although colitis also led to increase of TIMP-1 activity, the MMP-9/TIMP-1 balance remained elevated. Finally, in the MMP-9-deficient colitic mice both the extent and severity of intestinal epithelialinjury were significantly attenuated when compared with wt mice. CONCLUSION: We conclude that DSS induced colitis is markedly attenuated in animals lacking MMP-9. This suggests that intestinal injury induced by DSS is modu-lated by MMP-9 and that inhibition of this gelatinase may reduce inflammation.

Sodium selenite ameliorates dextran sulfate sodiuminduced chronic colitis in mice by decreasing Th1, Th17, and γδT and increasing CD4(+)CD25(+) regulatory T-cell responses

AIM To assess the effect of sodium selenite on the severity of dextran sulfate sodium(DSS)-induced colitis in C57BL/6 mice.METHODS Mice were randomly divided into four groups(n = 10/group): normal group, selenium(Se) group, chronic colitis group, and Se + chronic colitis group. The mice were sacrificed on day 26. Survival rates, clinical symptoms, colon length, and histological changes were determined. The percentages and absolute numbers of immune system cells in the lamina propria lymphocytes(LPL) of the colon, the expression of m RNA in colon tissue, and the concentrations of Th1, Th17, and Treg cytokines in LPL from the large intestine, were measured.RESULTS Se significantly ameliorated the symptoms of colitis and histological injury(P < 0.05 each), increasing the proportions of neutrophils and CD4+ CD25+ T cells(P < 0.05 each) and decreasing the proportions of γδT cells, CD4+, CD4+CD44+, and CD4+ CD69+ T cells in LPL(P < 0.05 each). Moreover, Se reduced the expression of IL-6, IFN-γ, IL-17 A, IL-21, T-bet, and RORγt(P < 0.05 each), but enhanced the expression of IL-10 and Foxp3(P < 0.05 each). CONCLUSION These results suggest that Se protects against DSSinduced chronic colitis perhaps by increasing the number of CD4(+)CD25(+) Tregs that suppress the secretion of proinflammatory cytokines and populations of Th1, Th17, and γδT cells.

Induction of experimental acute ulcerative colitis in rats by administration of dextran sulfate sodium at low concentration followed by intracolonic administration of 30% ethanol

Several models of experimental ulcerative colitis have been reported previously. However, none of these models showed the optimum characteristics. Although dextran sulfate sodium-induced colitis results in inflammation resembling ulcera-tive colitis, an obvious obstacle is that dextran sulfate sodium is very expensive. The aim of this study was to develop an inex-pensive model of colitis in rats. Sprague-Dawley rats were treated with 2% dextran sulfate sodium in drinking water for 3 d fol-lowed by an intracolonic administration of 30% ethanol. The administration of 2% dextran sulfate sodium followed by 30% ethanol induced significant weight loss, diarrhea and hematochezia in rats. Severe ulceration and inflammation of the distal part of rat colon were developed rapidly. Histological examination showed increased infiltration of polymorphonuclear leukocytes, lymphocytes and existence of cryptic abscesses and dysplasia. The model induced by dextran sulfate sodium at lower concentra-tion followed by 30% ethanol is characterized by a clinical course, localization of the lesions and histopathological features similar to human ulcerative colitis and fulfills the criteria set out at the beginning of this study.

Protective effect of decursin and decursinol angelate-rich Angelica gigas Nakai extract on dextran sulfate sodium-induced murine ulcerative colitis

Objective: To investigate the anti-inflammatory effects of decursin and decursinol angelate-rich Angelica gigas Nakai(AGNE) on dextran sulfate sodium(DSS)-induced murine ulcerative colitis(UC).Methods: The therapeutic effect of an AGNE was analyzed in a mouse model of UC induced by DSS. Disease activity index values were measured by clinical signs such as a weight loss, stool consistency, rectal bleeding and colon length. A histological analysis was performed using hematoxylin and eosin staining. Key inflammatory cytokines and mediators including IL-6, TNF-a, PGE2, COX-2 and HIF-1 a were assayed by enzymelinked immunosorbent assay or western blotting.Results: Treatment with the AGNE at 10, 20, and 40 mg/kg alleviated weight loss,decreased disease activity index scores, and reduced colon shortening in mice with DSSinduced UC. AGNE inhibited the production of IL-6 and TNF-a in serum and colon tissue. Moreover, AGNE suppressed the increased expression of COX-2 and HIF-1 a and the increased production of PGE2 in colon tissue were observed in mice with DSSinduced UC. Additionally, histological damage was also alleviated by AGNE treatment.Conclusions: The findings of this study verified that AGNE significantly improves clinical symptoms and reduces the activity of various inflammatory mediators. These results indicate the AGNE has the therapeutic potential in mice with DSS-induced UC.

Sodium arsenite reduces severity of dextran sulfate sodium-induced ulcerative colitis in rats

The histopathological features and the associated clinical findings of ulcerative colitis (UC) are due to persistent inflammatory response in the colon mucosa. Interventions that suppress this response benefit UC patients. We tested whether sodium arsenite (SA) benefits rats with dextran sulfate sodium (DSS)-colitis. The DSS-colitis was induced by 5% DSS in drinking water. SA (10 mg/kg; intraperitoneally) was given 8 h before DSS treatment and then every 48 h for 3 cycles of 7, 14 or 21 d. At the end of each cycle rats were sacrificed and colon sections processed for histological examination. DSS induced diarrhea, loose stools, hemoccult positive stools, gross bleeding, loss of body weight, loss of epithelium, crypt damage, depletion of goblet cells and infiltration of inflammatory cells. The severity of these changes increased in the order of Cycles 1, 2 and 3. Treatment of rats with SA significantly reduced this severity and improved the weight gain.

Longitudinal analysis of inflammation and microbiota dynamics in a model of mild chronic dextran sulfate sodium-induced colitis in mice

AIM: To characterize longitudinally the inflammation and the gut microbiota dynamics in a mouse model of dextran sulfate sodium (DSS)-induced colitis.

Calcitriol analog ZK191784 ameliorates acute and chronic dextran sodium sulfate-induced colitis by modulation of intestinal dendritic cell numbers and phenotype

AIM: To investigate the effects of ZK1916784, a low calcemic analog of calcitriol on intestinal inflammation. METHODS: Acute and chronic colitis was induced by dextran sodium sulfate (DSS) according to standard procedures. Mice were treated intraperitoneally with ZK1916784 or placebo and colonic inflammation was evaluated. Cytokine production by mesenterial lymph node (MLN) cells was measured by ELISA. Immunohistochemistry was performed to detect intestinal dendritic cells (DCs) within the colonic tissue, and the effect of the calcitriol analog on DCs was investigated. RESULTS: Treatment with ZK191784 resulted in significant amelioration of disease with a reduced histological score in acute and chronic intestinal inflammation. In animals with acute DSS colitis, down- regulation of colonic inflammation was associated with a dramatic reduction in the secretion of the proinflammatory cytokine interferon (IFN)-γ and a significant increase in intereleukin (IL)-10 by MLN cells. Similarly, in chronic colitis, IL-10 expression in colonic tissue increased 1.4-fold when mice were treated with ZK191784, whereas expression of the Th1-specific transcription factor T-beta decreased by 81.6%. Lower numbers of infiltrating activated CD11c+ DCs were found in the colon in ZK191784-treated mice with acute DSScolitis, and secretion of proinflammatory cytokines by primary mucosal DCs was inhibited in the presence of the calcitriol analog. CONCLUSION: The calcitriol analog ZK191784 demonstrated significant anti-inflammatory properties in experimental colitis that were at least partially mediated by the immunosuppressive effects of the derivate on mucosal DCs.

Anti-tumor necrosis factor α therapy associates to type 17 helper T lymphocytes immunological shift and significant microbial changes in dextran sodium sulphate colitis

BACKGROUND Anti-tumor necrosis factor α(TNFα) represents the best therapeutic option to induce mucosal healing and clinical remission in patients with moderate-severe ulcerative colitis. On the other side gut microbiota plays a crucial role in pathogenesis of ulcerative colitis but few information exists on how microbiota changes following anti-TNFα therapy and on microbiota role in mucosal healing.AIM To elucidate whether gut microbiota and immune system changes appear following anti TNFα therapy during dextran sulfate sodium(DSS) colitis.METHODS Eighty C57 BL/6 mice were divided into four groups: "No DSS", "No DSS + antiTNFα", "DSS" and "DSS + anti-TNFα". "DSS" and "DSS + anti-TNFα" were treated for 5 d with 3% DSS. At day 3, mice whithin "No DSS+anti-TNFα" and"DSS+anti-TNFα" group received 5 mg/kg of an anti-TNFα agent. Forty mice were sacrificed at day 5, forty at day 12, after one week of recovery post DSS. The severity of colitis was assessed by a clinical score(Disease Activity Index), colon length and histology. Bacteria such as Bacteroides, Clostridiaceae, Enterococcaceae and Fecalibacterium prausnitzii(F. prausnitzii) were evaluated by quantitative PCR.Type 1 helper T lymphocytes(Th1), type 17 helper T lymphocytes(Th17) and CD4+ regulatory T lymphocytes(Treg) distributions in the mesenteric lymph node(MLN) were studied by flow cytometry.RESULTS Bacteria associated with a healthy state(i.e., such as Bacteroides, Clostridiaceae and F. prausnitzii) decreased during colitis and increased in course of anti-TNFαtreatment. Conversely, microorganisms belonging to Enterococcaceae genera,which are linked to inflammatory processes, showed an opposite trend.Furthermore, in colitic mice treated with anti-TNFα microbial changes were associated with an initial increase(day 5 of the colitis) in Treg cells and a consequent decrease(day 12 post DSS) in Th1 and Th17 frequency cells. Healthy mice treated with anti-TNFα showed the same histological, microbial and immune features of untreated colitic mice. "No DSS + anti-TNFα" group showed a lymphomononuclear infiltrate both at 5 th and 12 th d at hematoxylin and eosin staining, an increase of in Th1 and Th17 frequency at day 12, an increase of Enterococcaceae at day 5, a decrease of Bacteroides and Clostridiaceae at day 12.CONCLUSION Anti-TNFα treatment in experimental model of colitis improves disease activity but it is associated to an increase in Th17 pathway together with gut microbiota alteration.

New approach of medicinal herbs and sulfasalazine mixture on ulcerative colitis induced by dextran sodium sulfate

BACKGROUND Sulfasalazine has been used as a standard-of-care in ulcerative colitis for decades,however,it results in severe adverse symptoms,such as hepatotoxicity,blood disorders,male infertility,and hypospermia.Accordingly,the new treatment strategy has to enhance pharmacological efficacy and stimultaneously minimize side effects.AIM To compare the anti-inflammatory action of sulfasalazine alone or in combination with herbal medicine for ulcerative colitis in a dextran sodium sulfate(DSS)-induced colitis mouse model.METHODS To induce ulcerative colitis,mice received 5%DSS in drinking water for 7 d.Animals were divided into five groups(n=9 each)for use as normal(non-DSS),DSS controls,DSS+sulfasalazine(30 mg/kg)-treatment experimentals,DSS+sulfasalazine(60 mg/kg)-treatment experimentals,DSS+sulfasalazine(30 mg/kg)+Citrus unshiu peel and Bupleuri radix mixture(30 mg/kg)(SCPB)-treatment experimentals.RESULTS The SCPB treatment showed an outstanding effectiveness in counteracting the ulcerative colitis,as evidenced by reduction in body weight,improvement in crypt morphology,increase in antioxidant defenses,down-regulation of proinflammatory proteins and cytokines,and inhibition of proteins related to apoptosis.CONCLUSIONSCPB may represent a promising alternative therapeutic against ulcerative colitis,without inducing adverse effects.

Antibody to eosinophil cationic protein suppresses dextran sulfate sodium-induced colitis in rats

AIM： To produce an antibody against rat eosinophil cationic protein （ECP） and to examine the effects of the antibody in rats with dextran sulfate sodium （DSS）-induced colitis. METHODS： An antibody was raised against rat ECP. Rats were treated with 3% DSS in drinking water for 7 d and received the antibody or normal serum. The colons were examined histologically and correlated with clinical symptoms. Immunohistochemistry and Western blot analysis were estimated as a grade of inflammation. RESULTS： The ECP antibody stained the activated eosinophils around the injured crypts in the colonic mucosa. Antibody treatment reduced the severity of colonic ulceration and acute clinical symptoms （diarrhea and/or bloodstained stool）. Body weight gain was significantly greater and the colon length was significantly longer in anti-ECPtreated rats than in normal serum-treated rats. Expression of ECP in activated eosinophils was associated with the presence of erosions and inflammation. The number of Ki-67-positive cells in the regenerated surface epithelium increased in anti-ECP-treated rats compared with normal serum-treated rats. Western blot analysis revealed reduced expression of macrophage migration inhibitory factor （MIF） in anti-ECP-treated rats. CONCLUSION： Our results indicate that treatment with ECP antibody, improved DSS-induced colitis in rats, possibly by increasing the regenerative activity of the colonic epithelium and downregulation of the immune response, and suggest that anti-ECP may promote intestinal wound healing in patients with ulcerative colitis （UC）.

Oral tolerance is inducible during active dextran sulfate sodium-induced colitis

AIM:To investigate whether oral tolerance is inducible during the active phase of dextran sulfate sodium(DSS)-induced colitis.METHODS:Colitis was induced in 6-to 8-wk-old female BALB/c mice by the administration of 2%DSS.To induce oral tolerance,mice that received water with DSS[DSS(+)]and mice that received autoclaved water[DSS(-)]were intragastrically(i.g.)administered ovalbumin(OVA)as a tolerogen before systemic challenge with OVA.Following this,serum levels of OVA-specific Ig E antibodies were measured.In mice with activecolitis,CD4+CD25+Foxp3+cell and B10 cell frequencies were evaluated using flow cytometry.Cytokine m RNA expression profiles were evaluated by reverse transcription real-time polymerase chain reaction.RESULTS:Regardless of the presence of DSS colitis,OVA-specific immunoglobulin E concentrations were significantly reduced in mice that were i.g.administered OVA compared to mice that were i.g.administered PBS[DSS(+):4.4(4.2-9.5)ng/m L vs 83.9(66.1-123.2)ng/m L,P<0.01;DSS(-):27.7(0.1-54.5)ng/m L vs116.5(80.6-213.6)ng/m L,P<0.01].These results demonstrated that oral tolerance was induced in both the presence and absence of colitis.In the spleen and mesenteric lymph nodes(MLN),the frequencies of CD4+CD25+Foxp3+cells and B10 cells,both of which are associated with oral tolerance,did not significantly change.In the spleen,interferon-γm RNA expression significantly decreased in mice with colitis[DSS(+):0.42(0.31-0.53)vs DSS(-):1.00(0.84-1.39),P<0.01].The expression levels of other cytokines did not significantly change.CONCLUSION:Oral tolerance is inducible during active DSS colitis.The stability of regulatory cell populations in the spleen and MLN in colitis might correlate with these results.