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.     

葡聚糖硫酸钠诱导小鼠实验性结肠炎的临床和组织病理学特征研究

目的研究葡聚糖硫酸钠(DSS)诱导小鼠实验性结肠炎的临床和病理特征,以便于指导选择合适的溃疡性结肠炎(ulcerative colitis,UC)小鼠模型。方法予3%DSS溶液喂饲野生型C57BL/6成年小鼠诱导急性结肠炎模型,分别于第0天、第3天、第5天、第7天和第10天麻醉处死小鼠,取结肠观察不同时期结肠病理学特征,造模过程中连续观察并记录小鼠体质量、大便和死亡情况。结果小鼠造模第3天开始出现粪便潜血,第5天开始出现血便,第10天开始出现死亡小鼠,死亡率为30%。DSS诱导小鼠急性结肠炎模型疾病活动指数第3天后与饮用纯净水的小鼠比较明显增高(P0.05)。小鼠结肠炎造模第3天黏膜上皮细胞开始逐渐丧失,第7~10天最为严重;隐窝结构的紊乱从第3天开始发生,第7天出现固有层塌陷;炎性细胞浸润从第3天开始数量逐渐增加,第10天最为严重。DSS诱导小鼠急性结肠炎模型结肠组织病理评分第5天后与饮用纯净水的小鼠比较明显增高(P0.05)。结论 3%DSS诱导野生型C57BL/6成年小鼠急性结肠炎模型可用于UC的实验研究,第3天出现明显的炎症表现,第7天模型较理想,小鼠死亡少。     

Effect of enteral nutrition on dextran sulfate sodium-induced colitis in rats

OBJECTIVE: To study the effect of enteral nutrition (EN) on dextran sulfate sodium (DSS)‐induced colitis in rats. METHODS: Eighty‐four Sprague–Dawley rats were divided into 7 groups (12 rats in each group). The blank control group was given ordinary laboratory feed and drinking water. The experimental groups received 5% DSS as drinking water for 7 days. Of the experimental groups, the model control group received ordinary laboratory feed, protein based enteral nutrition (PEN) was fed in the PEN group, while other groups received ordinary laboratory feed plus 5‐aminosalicylic acid (5‐ASA), methyl‐prednisolone, Lactobacillus or glutamine, respectively. On the 8th day, all the rats were sacrificed. Inflammatory scores were assessed from colonic mucosa. Blood culture from inferior vena cava, fecal culture and secretary immunoglobulin‐A (S‐IgA) levels from colonic contents were determined. RESULTS: Colon inflammatory scores of Lactobacillus, PEN, glutamine and drug‐treated groups were lower than that of the model control group (P < 0.01). The ratios of bacteria translocation in the EN (PEN, Lactobacillus and glutamine) groups were lower than that in the model control group (P < 0.0083). Fecal Lactobacilli in the Lactobacillus and glutamine groups were higher than that in the model control group (P < 0.05). S‐IgA levels in colonic contents of the PEN and 5‐ASA group were lower than that in the model control group (P < 0.05). CONCLUSIONS: EN is an effective therapy for treating DDS‐induced colitis. EN could alleviate damage, promote the repair of colonic epithelial cells and inhibit bacterial translocation. Lactobacillus and glutamine could also increase the Lactobacilli in colon.     

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 lymphocytes contributes to colitis progression at low dose of DSS stimulation. Lymphocytes may play roles as an aggravating factor in DSS-induced colitis.     

Effects of germinated barley foodstuff on dextran sulfate sodium-induced colitis in rats

Germinated barley foodstuff (GBF), derived from the aleurone and scutellum fractions of germinated barley, is rich in glutamine and low-lignified hemicellulose, and increases mucosal protein, RNA, and DNA content in the intestine when fed to normal rats. The aim of this study was to evaluate the effects of feeding GBF or germinated gramineous seeds on experimental ulcerative colitis. Sprague-Dawley rats that received 3% dextran sulfate sodium in their diets were used as an experimental colitis model. The effects of sulfasalazine, a drug used to treat inflammatory bowel disease, were compared with those of GBF. After rats had consumed diets containing GBF or various aleurone and scutellum fractions, mucosal damage; the content of mucosal protein, RNA, and DNA in the colo-rectum; and serum interleukin-8 and α₁-acid glycoprotein levels were assessed. GBF and germinated seeds more effectively prevented bloody diarrhea and mucosal damage in colitis compared with controls and rats receiving sulfasalazine, but non-germinated samples did not have a protective effect. GBF increased mucosal protein and RNA content in the colitis model. The consumption of GBF appears to prevent inflammation in a colitis model, and its effect seems to be related to the germination process. GBF and germinated seeds have the potential to serve as nutritional therapy for ulcerative colitis. (Received Mar. 17, 1997; accepted July 25, 1997)     

Compensatory response of colon tissue to dextran sulfate sodium-induced colitis

Depletion of goblet cells (the main mucin-producing cells in the colon) is one of the most reliable histological characteristics of ulcerative colitis, whereas a major symptom of this disease is bloody diarrhea containing a large amount of mucus. The discrepancy between these phenomena was investigated in a time-course study in rats with experimental colitis induced by treatment with oral dextran sulfate sodium (DSS) for 1, 3, or 5 days. Biochemical analysis showed a reduction in mucin content in the distal side of the colon that was proportional to the duration of DSS administration. In the proximal side of the colon, however, there was a significant increase in mucin content already on the first day of treatment with DSS. This increase in colonic mucin content continued for the 5 days of treatment. In the distal side, both sulfomucin and sialomucin decreased proportionally to the duration of DSS administration. In the proximal side, there was an increase in high iron diamine-Alcian blue-positive mucins, and confirming the proliferation of goblet cells. The proliferated glands were predominantly sialylated. Goblet cell depletion and an increase in mucin production occurred in different parts of the colon. This phenomenon may be a type of compensatory function of colon tissue in response to the localized decrease of mucin production in certain portions of the colon. (Received Sept. 7, 1998; accepted Nov. 27, 1998)     

凝结芽孢杆菌活菌TBC169株对右旋葡聚糖硫酸钠引发大鼠溃疡性结肠炎的治疗作用

目的:研究凝结芽胞杆茵(Bacillus coagulans,BC)对右旋葡聚糖硫酸钠(DSS)引发的大鼠溃疡性结肠炎(UC)的治疗作用.方法:采用DSS引发大鼠UC,分别用10~7和10~6 CFU/mL BC、0.02g/mL柳氮磺胺吡啶(SASP)和生理盐水(NS)处理.21d后测定动物体质量、结直肠湿重、肠黏膜溃疡、糜烂点数及面积、髓过氧化物酶活性和肠道菌群培养.结果:治疗21d后,各组中大鼠的体质量增加,以BC10~7 CFU/mL增重明显(P<0.05);各治疗组中大鼠的结直肠湿重、肠溃疡糜烂点数、面积、MPO活性与模型组比较均有显著性差异(P<0.05或P<0.01或P<0.001);肠道菌群分析,造型后双歧杆菌数明显下降(P<0.05),治疗后各组的双歧杆菌数量均明显增加(P<0.01或P<0.001),以BC组和SASP组增加最明显(P<0.01或P<0.001).BC在肠道定植.结论:BC对DSS引发的大鼠UC有明显治疗作用.     

Geranylgeranylacetone protects mice from dextran sulfate sodium-induced colitis

Objective. Geranylgeranylacetone (GGA) has recently been reported to induce heat shock protein (HSP) 70, which has a protective function against inflammation. We investigated the therapeutic effects of oral administration of GGA on dextran sulfate sodium (DSS)-induced colitis in mice.Material and methods. BALB/c mice were given 3% DSS solution orally for 7?days to induce colitis. The disease activity of colitis was assessed clinically every day, and histology in the colon was evaluated at 7?days post-DSS. The levels of myeloperoxidase (MPO) activity, tumor necrosis factor (TNF)-α and interferon (IFN)-γ in the colon tissues were also examined. In addition, expression of HSPs 25, 40, 70 and 90 in the colon tissue was determined by Western blot analysis. Mice were orally administered GGA (50–500?mg/kg) when treatment of DSS started.Results. It was found that GGA significantly reduced the clinical severity of colitis and suppressed the levels of MPO activity, TNF-α and IFN-γ induced by DSS in the colon. On the other hand, GGA enhanced the expression of HSP70 in the colon of mice given DSS. HSP70-positive cells were identified in the epithelial cells of the colon from mice treated with GGA and DSS.Conclusions. Taken together, these results suggest that GGA is a new anti-inflammatory drug that could be useful in the treatment of colitis such as inflammatory bowel disease.     

Dysplasia and carcinoma development in a repeated dextran sulfate sodium-induced colitis model

BACKGROUND: As an important mechanism underlying the increased risk of colorectal carcinoma development in patients with long-standing ulcerative colitis, promotion as a result of the regenerative process has been proposed. In the present study, a dysplasia-carcinoma sequence in a novel repeated colitis model in mice is documented. METHODS: Repeated colitis was induced by nine administration cycles of 3% dextran sulfate sodium (DSS; molecular weight, 54 000): each administration cycle comprised 3% DSS for 7 days followed by distilled water for the subsequent 14 days, to give conditions similar to the clinically observed active and remission phases in humans. RESULTS: Multiple colorectal tumors (nine low- and four high-grade dysplasias and two carcinomas) developed in 25 mice. These neoplastic lesions consisted of tubular structures, presenting as various types of elevated, flat and depressed tumor, similar to those in ulcerative colitis patients. A time-course study with assessment of the severity of colitis and in vivo bromodeoxyuridine uptake during a single 3% DSS administration cycle revealed a high level of regenerative activity in the colitis-affected mucosal epithelia. CONCLUSION: Thus, with the present repeated colitis model, regeneration and neoplastic lesions were apparent, the biological features of which provide evidence of a colorectal dysplasia-invasive carcinoma sequence in ulcerative colitis.     

Mucin production and composition is altered in dextran sulfate sodium-induced colitis in rats

We evaluated the small and large intestinal mucin production in a rat model of human ulcerative colitis by measuring the in vivo fractional synthesis rate (FSR) and the expression of mucins. A chronic colitis was induced by oral administration of 5% dextran sulfate sodium (DSS) for 9 days followed by 2% DSS for 18 days. DSS-treated rats showed increased colonic MUC2,3 mRNA levels compared pair-fed controls. The mucin FSR was unaffected while mucin-containing goblet cells were depleted in the vicinity of lesions. In the small intestine, no inflammatory lesions were observed but ileal MUC2 mRNA levels and mucin FSR were decreased by 46% and 21%, respectively. Finally, DSS-treated rats showed a marked decrease in mucin's threonine + serine content all along the gut, which may lead to a reduction of potential O-glycosylation sites. Our data indicate that the chronic colitis may impair the mucus layer protective function all along the gut.     

瑞巴匹特预防葡聚糖硫酸酯钠诱发的小鼠结肠炎疗效观察及作用机制初探

目的近年氧自由基在溃疡性结肠炎(UC)发病过程中作用受到关注,一种新型的黏膜保护剂瑞巴匹特被认为具有清除氧自由基的作用,有望成为治疗溃疡性结肠炎的新药物。本文观察瑞巴匹特灌肠和灌胃治疗葡聚糖硫酸酯钠(DSS)诱发的小鼠结肠炎效果并探讨可能的作用机制。方法 3%DSS予8周龄雄性BALB/c小鼠自由饮用7 d制成小鼠结肠炎模型。予DSS前5 d开始瑞巴匹特(45 mg/kg/d)灌肠或灌胃治疗直到造模结束,处死小鼠取结肠组织,测量小鼠体重、结肠长度,进行大体和病理评分,分光光度法测定髓过氧化物酶、丙二醛含量,免疫组化法测定核因子κB(NFκB)表达水平,RT-PCR法测定过氧化物酶体增殖体激活受体γ(PPARγ)mRNA表达。结果与安慰剂对照组比较,瑞巴匹特灌肠和灌胃治疗组小鼠大体和病理评分显著改善,髓过氧化物酶活性、丙二醛含量、NFκB活性明显降低,PPARγmRNA的表达显著升高。结论瑞巴匹特可有效预防DSS诱发的小鼠结肠炎,其抑制炎症作用至少部分与清除氧自由基,从而维持局部PPARγ表达和抑制NFκB活性有关。     

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.     

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.METHODS:In animal models,the most common method used to trigger colitis is based on the oral administration of the sulfated polysaccharides DSS.The murine DSS colitis model has been widely adopted to induce severe acute,chronic or semi-chronic colitis,and has been validated as an important model for the translation of mice data to human inflammatory bowel disease(IBD).However,it is now clear that models characterized by mild intestinal damage are more accurate for studying the effects of therapeutic agents.For this reason,we have developed a murine model of mild colitis to study longitudinally the inflammation and microbiota dynamics during the intestinal repair processes,and to obtain data suitable to support the recovery of gut microbiota-host homeostasis.RESULTS:All plasma cytokines evaluated,except IL-17,began to increase(P<0.05),after 7 d of DSS administration.IL-17 only began to increase 4 d after DSS withdrawal.IL-1βand IL-17 continue to increase during the recovery phase,even when clinical signs of colitis had disappeared.IL-6,IL-10 and IFN-γreached their maxima 4 d after DSS withdrawal and decreased during the late recovery phase.TNFαreached a peak(a three-fold increase,P<0.05),after which it slightly decreased,only to increase again close to the end of the recovery phase.DSS administration induced profound and rapid changes in the mice gut microbiota.After 3 d of DSS administration,we observed a major reduction in Bacteroidetes/Prevotella and a corresponding increase in Bacillaceae,with respect to control mice.In particular,Bacteroidetes/Prevotella decreased from a relative abundance of 59.42%-33.05%,while Bacillaceae showed a concomitant increase from 2.77%to 10.52%.Gut microbiota rapidly shifted toward a healthy profile during the recovery phase and returned normal 4 d after DSS withdrawal.Cyclooxygenase 2 expression started to increase 4 d after DSS withdrawal(P<0.05),when dysbiosis had recovered,and continued to increase during the recovery phase.Taken together,these data indicated that a chronic phase of intestinal inflammation,characterized by the absence of dysbiosis,could be obtained in mice using a single DSS cycle.CONCLUSION:Dysbiosis contributes to the local and systemic inflammation that occurs in the DSS model of colitis;however,chronic bowel inflammation is maintained even after recovery from dysbiosis.     

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.CONCLUSION SCPB may represent a promising alternative therapeutic against ulcerative colitis, without inducing adverse effects.