复方肠泰对葡聚糖硫酸钠诱导的溃疡性结肠炎治疗作用的研究

目的 探讨复方肠泰对葡聚糖硫酸钠(DSS)诱导的小鼠慢性溃疡性结肠炎(UC)的治疗作用。方法 随机将C57BL/6小鼠分为正常对照组、DSS模型组、复方肠泰给药组。采用2% DSS溶液对小鼠进行造模,小鼠连续5 d自由饮用DSS水,接着连续5 d自由饮水,重复3个循环。复方肠泰组每天按照18 g/kg ig给药,其他组ig给予相同体积的蒸馏水。每天记录小鼠体质量、疾病活动指数(DAI)评分结果,采用HE染色观察结直肠组织病理学变化,给予组织病理学评分;ELISA检测TNF-α、IL-10表达水平,免疫组化检测COX-2蛋白表达情况。结果 与DSS模型组比较,复方肠泰组小鼠疾病状态得到明显改善,DAI和组织病理学评分显著降低,炎症因子IL-10表达升高,TNF-α、COX-2蛋白的表达降低。结论 复方肠泰对小鼠慢性UC具有显著地治疗作用,可能通过促进抗炎症因子IL-10的表达,同时抑制促炎症因子TNF-α、COX-2蛋白的表达发挥作用。     

Balsalazine decreases intestinal mucosal permeability of dextran sulfate sodium-induced colitis in mice

Aim： To investigate the effect of balsalazine treatment on intestinal mucosal permeability in dextran sulfate sodium （DSS）-induced colitis and to determine the mechanism of the balsalazine-induced changes.
Methods： Experimental colitis was induced in C57BL/6J mice by the administration of 5% DSS. Balsalazine was administered intragastrically at doses of 42, 141, and 423 mg/kg. The disease activity index （DAI） score was evaluated and colon tissue was collected for the assessment of histological changes. The amount of malondialdehyde （MDA） in the colon was determined, along with the activity of myeloperoxidase （MPO）, superoxide dismutase （SOD） and glutathione peroxidase （GSH-Px）. Mucosa from the small intestine was collected to determine the levels of tumor necrosis factor （TNF）-α and interferon （IFN）-γ. The mucosa was ultrastructurally examined with transmission electron microscopy and intestinal permeability was assayed using Evans blue.
Results： Balsalazine was found to reduce the DAI score and the histological index （HI） score, decrease the MDA content and the activity of MPO, and increase the activity of SOD and GSH-Px in colitis mice. At the same time, balsalazine ameliorated microvillus and tight junction structure, resulting in a decrease in the amount of Evans blue permeating into the intestinal wall and the levels of TNF-α and IFN-γ in colitis mice.
Conclusion： In colitis mice, the anti-colitis effect of balsalazine results in a decrease in intestinal mucosal permeability. The mechanism of this effect is partly associated with balsalazine＇s antioxidative and anti-inflammatory effects.     

Therapeutic effects of Lactobacillus paracasei subsp. paracasei NTU 101 powder on dextran sulfate sodium-induced colitis in mice

Ulcerative colitis (UC) is a form of inflammatory bowel disease (IBD) whose exact cause is still unclear. Disruption of the intestinal microflora is considered one of the main causes of the disease. Lactobacillus paracasei subsp. paracasei NTU 101 (NTU 101) is a multifunctional strain that has been shown in previous studies to possess anti-inflammatory properties and to exert a modulatory effect on intestinal bacteria associated with certain pathogenic mechanisms of IBD. In the current study, we investigated the effects of NTU 101 on dextran sulfate sodium (DSS)-induced colitis in a mouse model. Colitis was induced in male C57BL/6 mice (total number n = 60) via dissolved DSS in drinking water on days 15–21 of the experiment. The effects of continuous 25 d feeding (days 0–25) of either a half or a full dose [2.3 × 10⁹ colony-forming units (CFU)/kg body weight (BW)/d and 4.5 × 10⁹ CFU/kg BW/d, respectively] of NTU 101 was evaluated. Lactobacillus rhamnosus BCRC 16000 (BCRC 16000) and L. paracasei subsp. paracasei BCRC 14023 (BCRC 14023) strains were given to control groups. The results indicated that NTU 101 powder improved anti-oxidant capacity, reduced pro-inflammatory cytokine levels, increased anti-inflammatory cytokine levels, and slightly ameliorated body weight loss in DSS-treated mice during the final days of the study. This indicated that NTU 101 powder can relieve the clinical symptoms of DSS-induced colitis in mice.     

Lansoprazole binding to the neutrophils in dextran sulfate sodium-induced rat colitis

To clarify the effector sites of lansoprazole in the colonic mucosa during the formation of colitis, dextran sulfate sodium-induced colitis was induced by the oral administration of 3% aqueous solution for 3 and 7 days. The effector sites of [³H]lansoprazole were examined by the intra-aortic infusion of the radiolabelled compound and the autoradiographic tracing of water-soluble compounds. As a result, the [³H]lansoprazole binding in the control rat colon was negligible, while in dextran sulfate sodium-treated rats specific binding sites of [³H]lansoprazole were recognized in the cytoplasm of the mesenchymal cells, and most of them coincided with polymorphonuclear leucocytes and macrophages.     

山姜素对葡聚糖硫酸钠诱导小鼠溃疡性结肠炎的保护作用及其作用机制研究

目的探讨山姜素对葡聚糖硫酸钠诱导的溃疡性结肠炎小鼠的保护作用及其作用机制。方法 C57BL/6小鼠随机分为对照组、模型组和25、50、100 mg/kg山姜素组。模型组和治疗组每天给予3%葡聚糖硫酸钠溶液,连续7 d。治疗组每日ip生理盐水0.5 m L+25、50、100 mg/kg山姜素,对照组和模型组每天ip生理盐水0.5 m L,连续7 d。观察小鼠体质量变化、结肠长度、疾病活动指数(DAI)评分、组织学损伤评分等炎症反应;透射电镜观察肠上皮细胞间连接;免疫组织化学法、Western blotting法检测肠道紧密连接蛋白claudin-2、occludin、ZO-1、STAT3、p STAT3、IL-6的表达和STAT3/IL-6信号通路的表达情况。结果与模型组比较,山姜素能够显著缓解小鼠体质量减轻和肠管缩短,降低DAI和组织学评分。山姜素可增强小鼠肠黏膜occludin、ZO-1表达,减弱claudin-2表达,并能够抑制STAT3/IL-6信号通路。结论山姜素能够上调葡聚糖硫酸钠诱导的溃疡性结肠炎小鼠结肠组织occludin、ZO-1的表达,下调claudin-2的表达,通过调节紧密连接蛋白的表达,保护肠上皮细胞屏障的完整性和通透性。通过抑制IL-6/STAT3通路,减轻结肠炎症反应。     

N-乙酰半胱氨酸对葡聚糖硫酸钠诱导的小鼠溃疡性结肠炎的保护作用

目的观察N-乙酰半胱氨酸(NAC)灌肠对小鼠急性溃疡性结肠炎的作用。方法5%葡聚糖硫酸钠(DSS)自由饮用7 d诱导小鼠急性溃疡性结肠炎,同时予以生理盐水(NS)、5-氨基水杨酸(5-ASA)、NAC保留灌肠,观察小鼠体重、粪便性状、隐血便血,计算疾病活动度(DAI)积分,检测结肠长度、结肠过氧化物酶(MPO)活性、血清过氧化物歧化酶(SOD)活力和丙二醛(MDA)含量及肠黏膜病理改变。结果NAC组小鼠隐血、便血、体重下降、DAI积分、病理改变等均好于模型组、NS组(P<0.05),与5-ASA组疗效相似。NAC组SOD活力高于模型组,MPO活性、MDA含量则低于模型组(P<0.05)。结论NAC对DSS诱导的小鼠急性溃疡性结肠炎黏膜损伤有保护作用,其机制可能与抗氧化应激有关。     

The protective effect of syringic acid on dextran sulfate sodium-induced experimental colitis in BALB/c mice

Inflammatory bowel diseases involve chronic intestinal inflammation which is mostly caused by Crohn's disease and ulcerative colitis (UC) conditions. Patients having UC are prone to colorectal cancer and dysplastic polyps, and also have sporadic adenomas. Syringic acid (SA) possesses many health benefits including antioxidant, anti-bacterial, and anti-cancer. This study was aimed to identify the effects of SA on UC, using a murine experimental model. Clinical symptoms and weight loss were significantly reduced in mice induced with dextran sulfate sodium (DSS) and treated with SA, compared to untreated mice. The effects of SA exhibited in DSS-induced mice were associated with significant decrease in the expressions levels of inflammatory mediators such as inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), pro-inflammatory cytokines (tumor necrosis factor [TNF-α], interleukin [IL-1β and IL-6]), remarkable amelioration of colonic architectural disruption, and a significant reduction in the activity of colonic myeloperoxidase. To further confirm the anti-inflammatory property of SA, RAW 264.7 cells were stimulated with lipopolysaccharides. SA dose-dependently inhibited the cytokines TNF-α, IL-1β, and IL-6. It also decreased the expressions of p65-NF-κB and IκB, thus reducing the activation and nuclear accumulation of p-STAT-3^Y705. This prohibited the degradation of inhibitory protein, IκB, as well as inhibited the nuclear translocation of p65-NF-κB in colonic tissue. It was concluded that SA has a potential to limit inflammation via inhibiting the p65-NF-κB and STAT3 signaling; hence it can be used for therapeutic purposes.     

Phenyl methimazole suppresses dextran sulfate sodium-induced murine colitis

Ulcerative colitis is an autoimmune-inflammatory disease characterized by abnormally increased expression of Toll-like receptor-4 (TLR4) in colonic epithelial cells, increased production of pro-inflammatory cytokines (e.g., TNF-α, IL-1β, IL-6, IL-12), chemokines (e.g., IP-10), and endothelial cell adhesion molecules (e.g., VCAM-1), plus enhanced leukocyte infiltration into colonic interstitium. Previously, we have shown that phenyl methimazole (C10) markedly decreases virally-induced TLR-3 expression and signaling and potently inhibits both TNF-α-induced VCAM-1 expression and the resultant leukocyte-endothelial cell adhesion. In this study we probed the hypothesis that C10 is efficacious in a TLR-4- and VCAM-1-associated murine model [the dextran sulfate sodium (DSS) model] of human colitis. C10 was administered intraperitoneally coincident with or after DSS treatment was initiated. Macroscopic colon observations revealed that C10 significantly reversed DSS-induced shortening of the colon (P < 0.05) and reduced the presence of blood in the colon. Histological analyses of colonic tissues revealed that C10 distinctly attenuated both DSS-induced edema as well as leukocyte infiltration in the colonic mucosa and resulted in pronounced protection against DSS-induced crypt damage (P < 0.001). Northern blot analyses and immunohistochemistry of colonic tissue revealed that C10 markedly diminished DSS-induced expression of pertinent inflammatory mediators: TNF-α, IL-1β, IL-6, IL-12, IP-10, TLR-4 and VCAM-1. Most importantly, C10 significantly improved survival and protected mice against DSS-induced colitic-death: 75% by comparison to 12.5% with identical treatment with DMSO-control (log rank test: P = 0.005). These results provide direct evidence that C10 suppresses DSS-induced colitis by inhibiting expression of key inflammatory mediators and leukocyte infiltration, and is a potentially attractive therapeutic for colitis.     

Transplantation of human umbilical mesenchymal stem cells attenuates dextran sulfate sodium‐induced colitis in mice

Ulcerative colitis is a major form of inflammatory bowel disease and increases the risk of the development of colorectal carcinoma. The anti‐inflammatory and immunomodulatory properties of mesenchymal stem cells (MSC) make them promising tools for treating immune‐mediated and inflammatory diseases. However, the lack of robust technique for harvesting and expanding of MSC has hampered the use of bone marrow and umbilical cord blood derived MSC in clinical applications. In the present study, we investigated the intestinal protective effects of Wharton's jelly‐derived umbilical MSC (UMSC) on dextran sulfate sodium‐induced colitis in mice. The severity of colitis in mice was assessed using bodyweight loss, stool consistency, rectal bleeding, colon shortening and haematological parameters. Colonic myeloperoxidase and pro‐inflammatory cytokines levels were also measured. Furthermore, the expression of cyclooxygenase 2 and inducible nitric oxide synthase in the colon were detected. In addition, intestinal permeability and tight junction proteins expressions in the colon were examined as well. The results showed that Wharton's jelly‐derived UMSC significantly diminished the severity of colitis, reduced histolopathological score, and decreased myeloperoxidase activity and cytokines levels. Furthermore, the UMSC markedly decreased the expression of cyclooxygenase 2and inducible nitric oxide synthase in the colon. In addition, transplantation of UMSC reduced intestinal permeability and upregulated the expression of tight junction proteins. These results show that the anti‐inflammation and regulation of tight junction proteins by Wharton's jelly‐derived UMSC ameliorates colitis.     

Dextran sulfate sodium-induced colitis-associated neoplasia： a promising model for the development of chemopreventive interventions

Individuals diagnosed with ulcerative colitis face a significantly increased risk of developing colorectal dysplasia and cancer during their lifetime. To date, little attention has been given to the development of a chemopreventive intervention for this high-risk population. The mouse model of dextran sulfate sodium （DSS） - induced colitis represents an excellent preclinical system in which to both charac- terize the molecular events required for tumor formation in the presence of inflam- mation and assess the ability of select agents to inhibit this process. Cyclic admin- istration of DSS in drinking water results in the establishment of chronic colitis and the development of colorectal dysplasias and cancers with pathological fea- tures that resemble those of human colitis-associated neoplasia. The incidence and multiplicity of lesions observed varies depending on the mouse strain used （ie, Swiss Webster, C57BL/6J, CBA, ICR） and the dose （0.7%-5.0%） and schedule （1-15 cycles with or without a subsequent recovery period） of DSS. The incidence of neoplasia can be increased and its progression to invasive cancer accelerated significantly by administering DSS in combination with a known colon carcinogen （azoxymethane （AOM）, 2-amino-3-methylimidazo[4,5-f]quinoline （IQ）, 2-amino-1- methyl-6-phenylimidazo[4,5-b]pyridine （PhIP）） or iron. More recent induction of colitis-associated neoplasia in genetically defined mouse strains has provided new insight into the role of specific genes （ie, adenomatous polyposis coli （Apc）, p53, inducible nitric oxide synthase （iNOS）, Msh2） in the development of colitis- associated neoplasias. Emerging data from chemopreventive intervention studies document the efficacy of several agents in inhibiting DSS-induced neoplasia and provide great promise that colitis-associated colorectal neoplasia is a preventable disease.     

A new flavonoid derivative, dosmalfate, attenuates the development of dextran sulphate sodium-induced colitis in mice

In this study, we have evaluated the efficacy of dosmalfate, a new flavonoid derivative compound, for the prevention and treatment of experimental colitis. To induce colitis, BALB/c mice received 5% dextran sulphate sodium (DSS) in their drinking water continuously for 7 days. Colitis was quantified by a clinical damage score, colon length, weight loss, stool consistency and rectal bleeding. Inflammatory response was assessed by neutrophil infiltration, determined by histology and myeloperoxidase (MPO) activity. Interleukin (IL)-1 beta, prostaglandins (PG)E(2) and (PG)D(2) concentrations in colonic tissue, histological and histochemical analysis of the lesions were also measured. Dosmalfate (400-800 mg/kg body weight, p.o.) ameliorated severe colitis reduced the degree of inflammation through reduction of neutrophil infiltration and IL-1 beta levels. (PG)E(2) and (PG)D(2) synthesis were significantly reduced in colitis control group and treatment with dosmalfate abolished the decrease in PG synthesis in colon mucosa. We conclude that dosmalfate is protective in acute DSS-induced colitis. The beneficial effects seem to be related to a decrease of neutrophil infiltration, absence of up-regulation of IL-1 beta and increase of PG production in colon mucosa.     

葡聚糖硫酸钠自由饮用与灌胃诱导小鼠溃疡性结肠炎模型的比较

目的比较不同浓度葡聚糖硫酸钠(dextran sulfate sodium,DSS)在自由饮用和灌胃两种方式下诱导小鼠急性溃疡性结肠炎(ulcerative colitis,UC)成模情况和模型相关指标变异系数,优选UC造模方法。方法小鼠随机分为正常组、3%DSS溶液自由饮用组、4%DSS溶液自由饮用组、30%DSS溶液灌胃组、40%DSS溶液灌胃组。灌胃组晚于自由饮用组1 d开始给予DSS,30%DSS灌胃组和40%DSS溶液灌胃组的灌胃剂量分别与3%DSS饮用组、4%DSS饮用组小鼠前1 d摄入DSS的平均剂量相等。观察记录小鼠体质量、食量、疾病活动指数(DAI)、主要脏器指数、结肠长度及组织病理学评分,比较不同造模方法上述各指标变异系数。结果4种造模方式均能成功诱导UC。其中,3%DSS自由饮用组在动物存活率、造模成本和操作方便程度方面优于其他造模方法,各指标变异系数未明显高于其他方法。结论3%DSS溶液自由饮用法是本实验中小鼠急性UC较合适的造模方法。     

Effects of nimesulide,a cyclooxygenase-2 selective inhibitor,on colitis induced tumors

Cyclooxygenase-2 (COX-2) is known to suppress sporadic colorectal cancer, but effect of selective COX-2 inhibitor in UC-associated neoplasia is still unknown. This study investigated effect of a selective COX-2 inhibitor on colorectal carcinogenesis in experimental murine UC. Chronic colitis was induced in mice by four cycles of administration of dextran sulfate sodium (DSS) (i. e., 5 % DSS for 7 days and distilled water for the following 14 days), and the mice were sacrificed 120 days after the end of the fourth cycle. The mice were divided into the following five groups: Group A, served as a disease control; Group B, received a diet mixed with 400 ppm of nimesulide (NIM), a selective COX-2 inhibitor, during the whole period; Group C, received NIM during the four cycles of DSS administration; Group D, received NIM for 120 days from the end of the fourth cycle; Group E, served as a normal control. In Group D, NIM significantly suppressed the occurrence of dysplasia and/or cancer. The results show that NIM inhibited both dysplasia and cancer in DSS-treated mice, thus showing that NIM has preventive effects on the remission phase of carcinogenesis. Received 20 July 2006; revised 21 August 2006; accepted 4 September 2006     

The effective therapy of cyclosporine A with drug delivery system in experimental colitis

Cyclosporine A (CyA) is a useful immunosuppressive agent for steroid-dependent or steroid-refractory ulcerative colitis. However, side effects have been reported in clinical trials of ulcerative colitis treated with CyA. Biodegradable microspheres (MS) have been investigated as drug delivery system. We evaluated the effect of a drug delivery system with poly(d,l-lactic acid)-MS containing CyA. Colitis was induced in C57BL/6 mice by 3% dextran sulfate sodium (DSS). Mice with DSS-induced colitis were treated with oral administration of CyA or CyA-MS: CyA (0.2?mg/kg/day)-MS; CyA (2?mg/kg/kg)-MS). Serum levels of CyA were significantly less elevated after oral administration of CyA (2?mg/kg/day)-MS compared with CyA (2?mg/kg/day) (CyA (2?mg/kg/day), 44.7 ± 0.8?ng/ml; CyA (2?mg/kg/day)-MS, 7.7 ± 1.3?ng/ml). The body weight at day 10 was significantly recovered in the mice treated with CyA (0.2?mg/kg/day)-MS and CyA (2?mg/kg/day)-MS compared with CyA (0). The histological score and myeloperoxidase activity in the mice treated with CyA-MS was significantly lower than CyA (0). Gene expressions of interleukin-1β (IL-1β), IL-6, and CXCL1 in the mice treated with CyA (0.2?mg/kg/day)-MS and CyA (2?mg/kg/day)-MS were downregulated compared with CyA (0)-MS. CyA-MS might be possible to treat ulcerative colitis effectively by decreasing the total dosage without the elevation of the serum level or the side effects of CyA.     

Evaluation of the anti-inflammatory effect of baicalein on dextran sulfate sodium-induced colitis in mice

The anti-inflammatory effect of three flavonoids from the root of Scutellaria baicalensis (baicalein, baicalin and wogonin) was evaluated in a murine model of acute experimental colitis induced by dextran sulfate sodium (DSS). Baicalein, but not baicalin or wogonin, given orally at 20 mg/kg for ten days, ameliorates all the considered inflammatory symptoms of the induced colitis, such as body weight loss, blood haemoglobin content, rectal bleeding and other histological and biochemical parameters. The effect of baicalein was similar to that of sulfasalazine, the reference drug given at 50 mg/kg.     

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.