The vagus nerve: a tonic inhibitory influence associated with inflammatory bowel disease in a murine model

BACKGROUND & AIMS: The recently proposed Inflammatory Reflex describes an interaction between the vagus nerve and peripheral macrophages, resulting in attenuation of proinflammatory cytokine release in response to systemic exposure to bacterial endotoxin. The purpose of this study was to determine whether a similar vagus/macrophage axis modulates the inflammatory responses in the colon in mice. METHODS: We assessed the Disease Activity Index (DAI), macroscopic and histologic damage, serum amyloid-P level, and myeloperoxidase activity in colitis induced by administration of dextran sodium sulfate (DSS) in healthy and vagotomized C57BL/6 and in mice deficient in macrophage-colony stimulating factor (M-CSF)-induced and in hapten-induced colitis. A pyloroplasty was performed in vagotomized mice. RESULTS: DAI, macroscopic and histologic scores, myeloperoxidase activity, levels of serum amyloid-P, and colonic tissue levels of interleukin (IL)-1beta, IL-6, and tumor necrosis factor-alpha were increased significantly in vagotomized mice 5 days post-DSS and 3 days after hapten-induced colitis compared with sham-operated mice that received DSS or the hapten. Pretreatment with nicotine significantly decreased each of these markers in vagotomized mice with DSS colitis, and all markers except DAI and IL-6 in sham-operated DSS-treated mice. Conversely, hexamethonium treatment significantly increased each of these markers in the sham-operated DSS-treated mice. Vagotomy had no effect on the colitis in M-CSF-deficient mice. CONCLUSIONS: The vagus nerve plays a counterinflammatory role in acute colitis via a macrophage-dependent mechanism, involving hexamethonium-sensitive nicotinic receptors. The identification of a counterinflammatory neural pathway would open new therapeutic avenues for treating acute exacerbations of inflammatory bowel disease.     

The Role of Zinc and Metallothionein in the Dextran Sulfate Sodium-Induced Colitis Mouse Model

Zinc (Zn) and its binding protein metallothionien (MT) have been proposed to suppress the disease activity in ulcerative colitis. To determine the role of Zn and MT in the dextran sulfate sodium (DSS)-induced model of colitis in mice, a DSS dose-response study was conducted in male C57BL/6 wild-type (MT+/+) and MT-null (MT−/−) mice by supplementing 2%, 3%, and 4% DSS in the drinking water for 6 days. In the intervention study, colitis was induced with 2% DSS, Zn (24 mg/ml as ZnO) was gavaged (0.1 ml) daily, concurrent with DSS administration, and the disease activity index (DAI) was scored daily. Histology, MT levels, and myeloperoxidase (MPO) activity were determined. DAI was increased (P<0.05) by 16% and 21% with 3% and 4% concentrations of DSS, respectively, compared to 2%, evident after 5 days of DSS administration. MPO activity was increased in MT+/+ compared to MT−/− mice and those receiving DSS. Zn administration had a 50% (P<0.05) lower DAI compared to DSS alone. Zn partially prevented the distal colon of MT+/+ by 47% from DSS-induced damage compared to MT−/− mice. MT did not prevent DSS-induced colitis and Zn was partially effective in amelioration of DSS-induced colitis.     

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.     

慢性应激对小鼠溃疡性结肠炎的影响

目的观察慢性束缚应激对葡聚糖酸钠(DSS)诱导的小鼠溃疡性结肠炎(UC)的影响。方法64只BALB/C小鼠分为6组,单纯应激组、正常对照组各16只,应激 2DSS组、应激 4DSS组、2DSS组、4DSS组各8只。采用自制的束缚笼对应激组小鼠建立慢性心理应激动物模型。采用小鼠自由饮用DSS溶液的方法建立UC模型。每日观察各组疾病活动指数(DAI)。并在实验结束后测量结肠组织损伤评分(HS)、髓过氧化物酶(MPO)活性。HS评分通过在光镜下观察结肠组织学改变得出。并用分光光度法测定结肠组织中MPO的活性。结果单纯应激组小鼠体重增长较正常对照组缓慢(P<0.05)。4DSS组小鼠DAI评分、HS评分及结肠组织MPO活性均较正常对照组增高(P<0.05)。应激 4DSS组上述指标较正常对照组变化更显著,与4DSS组比较亦增高(P<0.05)。2DSS组上述指标与正常对照组相比无明显区别(P>0.05)。应激 2DSS组上述指标较正常对照组增高(P<0.05)。结论慢性束缚应激可以使小鼠发生UC的易感性增加并加重DSS结肠炎的病理损伤。     

Wuchereria bancrofti macrophage migration inhibitory factor-2 (rWbaMIF-2) ameliorates experimental colitis

Immunomodulatory molecules produced by helminth parasites are receiving much attention recently as novel therapeutic agents for inflammation and autoimmune diseases. In this study, we show that macrophage migration inhibitory factor (MIF) homologue from the filarial parasite, Wuchereria bancrofti (rWbaMIF-2), can suppress inflammation in a dextran sulphate sodium salt (DSS)-induced colitis model. The disease activity index (DAI) in DSS given mice showed loss of body weight and bloody diarrhoea. At autopsy, colon of these mice showed severe inflammation and reduced length. Administration of rWbaMIF-2 significantly reduced the DAI in DSS-induced colitis mice. rWbaMIF-2-treated mice had no blood in the stools, and their colon length was similar to the normal colon with minimal inflammation and histological changes. Pro-inflammatory cytokine genes (TNF-α, IL-6, IFN-γ, IL-1β, IL-17A and NOS2) were downregulated in the colon tissue and peritoneal macrophages of rWbaMIF-2-treated mice. However, there were significant increases in IL-10-producing Treg and B1 cells in the colon and peritoneal cavity of rWbaMIF-2-treated mice. These findings suggested that rWbaMIF-2 treatment significantly ameliorated the clinical symptoms, inflammation and colon pathology in DSS given mice. This immunomodulatory effect of rWbaMIF-2 appeared to be by promoting the infiltration of Treg cells into the colon.     

A recombinant cystatin from Ascaris lumbricoides attenuates inflammation of DSS‐induced colitis

Helminthiasis may ameliorate inflammatory diseases, such as inflammatory bowel disease and asthma. Information about immunomodulators from Ascaris lumbricoides is scarce, but could be important considering the co‐evolutionary relationships between helminths and humans. We evaluated the immunomodulatory effects of a recombinant cystatin from A. lumbricoides on an acute model of dextran sodium sulphate (DSS)‐induced colitis in mice. From an A. lumbricoides cDNA library, we obtained a recombinant cystatin (rAl‐CPI). Protease activity inhibition was demonstrated on cathepsin B and papain. Immunomodulatory effects were evaluated at two intraperitoneal doses (0.5 and 0.25 μg/G) on mice with DSS‐induced colitis. Body weight, colon length, Disease Activity Index (DAI), histological inflammation score, myeloperoxidase (MPO) activity, gene expression of cytokines and cytokines levels in colon tissue were analysed. Treatment with rAl‐CPI significantly reduced DAI, MPO activity and inflammation score without toxic effects. Also, IL‐10 and TGF‐B gene overexpression was observed in rAl‐CPI‐treated group compared to DSS‐exposed control and healthy mice. Furthermore, a reduction in IL‐6 and TNF‐A expression was found, and this was confirmed by the levels of these cytokines in colonic tissue. In conclusion, rAl‐CPI reduces inflammation in a mouse model of DSS‐induced colitis, probably by increasing the expression of anti‐inflammatory cytokines and reducing pro‐inflammatory ones.     

源自日本血吸虫的半胱氨酸蛋白酶抑制剂对葡聚糖硫酸钠诱导的小鼠溃疡性结肠炎的影响

目的 探讨日本血吸虫半胱氨酸蛋白酶抑制剂（Schistosoma japonicum cysteine protease inhibitor,SjCystatin）对葡聚糖硫酸钠（Dextransulphate sodium,DSS）诱导的小鼠急性溃疡性结肠炎的抑制作用。方法 18只雌性C57BL/6小鼠随机分为3组：A组为对照组,B组为肠炎组,C组为SjCystatin治疗组。A组给予蒸馏水,B、C组连续饮用3％DSS溶液7 d诱发肠炎;C组每天经腹腔注射10 μg SjCystatin,A和B组注射PBS。观察各组小鼠临床表现,进行临床疾病活动指数（Disease activity index,DAI）评分。第7天处死小鼠,观察结肠大体及组织病理改变。同时提取小鼠结肠组织匀浆,采用酶联免疫吸附实验（ELISA）测定其上清中肿瘤坏死因子?α（TNF?α）、白细胞介素?4（IL?4）、IL?6及IL?10水平。结果 与A组[（[0.50±0.28]）分]相比,B组小鼠DAI评分[（[9.30±1.30]）分]明显增加,建模后小鼠结肠病理损伤显著,结肠组织匀浆上清中TNF?α为（321.33 ± 67.01） pg/mL,IL?6为（403.58 ± 180.51） pg/mL,均明显上升。C组小鼠DAI评分为（[6.67±1.57]）分,显著下降（F = 86.86,P < 0.01）;小鼠结肠大体及组织病理明显缓解,结肠组织匀浆上清中TNF?α为（188.14 ± 40.14） pg/mL,IL?6为（209.71 ± 48.47） pg/mL,均显著下降（F = 17.46、9.89, P < 0.01）。结论 SjCystatin对DSS诱导的C57BL/6小鼠急性溃疡性结肠炎有抑制效果。     

Inducible nitric oxide synthase from bone marrow-derived cells plays a critical role in regulating colonic inflammation

BACKGROUND & AIMS: Nitric oxide (NO) is an important mediator of intestinal inflammation. Inducible NO synthase (iNOS) is the main source of NO in inflammation. Because iNOS is ubiquitously expressed, our aim was to determine which cellular source(s) of iNOS plays the central role in mediating intestinal inflammation. METHODS: Chimeric lines were produced via bone marrow (BM) transplantation following irradiation. Colitis was induced with dextran sodium sulfate (DSS) or trinitrobenzene sulfonic acid (TNBS). The severity of colitis and markers of inflammation were assessed in standard fashion. Leukocyte recruitment was assessed by intravital microscopy. RESULTS: The irradiated chimeric lines with iNOS-/- BM-derived cells were markedly more resistant to both DSS- and TNBS-induced injury. Resistance to DSS-induced colitis was lost when wild-type (wt) BM was used to reconstitute iNOS-/- mice. Neutrophils were the main source of iNOS in DSS-induced colitis. iNOS-/- chimeric lines had decreased colonic macrophage inflammatory protein 1beta and tumor necrosis factor alpha expression and increased levels of the protective growth factor, keratinocyte growth factor. LPS-mediated leukocyte recruitment was reduced in iNOS-/- mice, and there were marked changes in the inflammatory cell infiltrates between the chimeric lines with iNOS-/- vs wt BM-derived cells. Furthermore, the lamina propria CD4 +ve cells from chimeric lines with iNOS-/- BM-derived cells had reduced intracellular cytokine expression. CONCLUSIONS: iNOS produced by BM-derived cells plays a critical role in mediating the inflammatory response during colitis. Cell-specific regulation of iNOS may represent a novel form of therapy for patients with inflammatory bowel disease.     

Vanilloid receptor-1 containing primary sensory neurones mediate dextran sulphate sodium induced colitis in rats

BACKGROUND AND AIMS: The role of sensory neurones in colitis was studied by chemical denervation of primary sensory neurones as well as antagonism of the vanilloid receptor-1 (VR-1) in rats prior to administration of dextran sulphate sodium (DSS) to induce colitis. METHODS: Neonatal rats were chemically denervated by subcutaneous administration of capsaicin; controls received capsaicin vehicle only. When animals reached maturity, colitis was induced by administration of 5% DSS in drinking water for seven days. Additionally, normal adult rats were treated with a VR-1 antagonist capsazepine (CPZ) or vehicle twice daily via an enema from day 0 to day 6 of the DSS regimen. Control rats were treated with an enema infusion of vehicle and 5% DSS, or without either an enema infusion or DSS in drinking water. For both groups of rats, severity of inflammation was quantitated by disease activity index (DAI), myeloperoxidase (MPO) activity, and histological examination. RESULTS: DSS induced active colitis in all control rats with resultant epithelial ulceration, crypt shortening, and neutrophil infiltration. Both neonatal capsaicinised rats and normal adult rats treated with CPZ enemas exhibited significantly lower levels of DAI, MPO, and histological damage compared with vehicle treated rats (p< 0.05). CONCLUSIONS: Neonatal capsaicinisation and local administration of CPZ prevents intestinal inflammation in a well established model of colitis indicating that primary sensory neurones possessing VR-1 receptors are required in the propagation of colonic inflammation.     

Polaprezinc (N-(3-aminopropionyl)-L-histidinato zinc) ameliorates dextran sulfate sodium-induced colitis in mice

OBJECTIVE: Polaprezinc (N-(3-Aminopropionyl)-L-histidinato zinc), an anti-ulcer drug, has been reported to have an anti-inflammatory action in several inflammatory diseases. The aim of this study was to investigate the effect of polaprezinc on dextran sulfate (DSS)-induced colitis in mice. MATERIAL AND METHODS: Mice with colitis induced by DSS were intrarectally treated with polaprezinc (15 mg/kg) or zinc sulfate (7.5 mg/kg) every day after the administration of DSS for 7 days. Disease activity index (DAI) and histological tissue damage were assessed. Levels of myeloperoxidase (MPO) activity, tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma in the colon were measured. Expression of heat shock protein (HSP) 25 and HSP70 in the colon was analyzed by Western blot analysis. RESULTS: DAI and histological scores were remarkably reduced in polaprezinc-treated mice with DSS-induced colitis. Polaprezinc suppressed the increase of MPO activity and the production of TNF-alpha and IFN-gamma in the colon tissues of mice with DSS-induced colitis. Expression of HSP25 and HSP70 was remarkably up-regulated in the colon tissues of polaprezinc-treated mice during DSS treatment. CONCLUSIONS: Polaprezinc suppresses DSS-induced colitis in mice, partly through inhibition of production of pro-inflammatory cytokine, suppression of neutrophils accumulation and cytoprotection by overexpression of HSPs. Polaprezinc could be useful in the treatment of inflammatory bowel diseases.     

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. MATERIALS 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)-alpha and interferon (IFN)-gamma 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-alpha and IFN-gamma induced by DSS in the colon. On the other hand, GGA enhanced the expression of HSP70 in the colon of mice given 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.     

Amelioration of murine dextran sulfate sodium-induced colitis by ex vivo extracellular superoxide dismutase gene transfer

BACKGROUND: Although the etiology of inflammatory bowel disease has not been fully clarified, reactive oxygen species is speculated to be involved. Extracellular superoxide dismutase (EC-SOD), an isozyme of SODs, is known to function mainly in body fluids. We investigated the efficacy of an ex vivo EC-SOD gene transfer into dextran sulfate sodium (DSS)-induced colitis mice. MATERIALS AND METHODS: Experimental colitis was induced by providing Balb/c mice with DSS in sterile distilled water provided as desired. The syngenic fibroblasts were obtained from Balb/c mice embryos and retrovirally transduced with the hEC-SOD gene. These engineered cells were confirmed to secrete EC-SOD in culture medium by enzyme-linked immunosorbent assay and were inoculated subcutaneously in the backs of DSS-treated mice. Mucosal injury of the colon was evaluated by the disease activity index (DAI: body weight, rectal bleeding, and stool consistency), grading of histologic disease severity, and levels of cytokine (tumor necrosis factor-alpha, interleukin-1beta) production. 8-Hydroxydeoxyguanosine (8-OHdG) levels in the mucosal tissue were assessed by immunohistochemical staining. Malondialdehyde (MDA) was measured using a colorimetric assay. RESULTS: A significant improvement was observed in DAI score and histologic severity as well as in mucosal tissue levels of inflammatory cytokines, 8-OHdG, and MDA of mice treated with the EC-SOD gene as compared with those without gene therapy, not only in a mild colitis model but also in a severe colitis model. Survival of treated mice in these models was significantly prolonged. CONCLUSIONS: Ex vivo transfer of the EC-SOD gene was feasible for treatment of DSS-induced colitis.     

The role of the resident intestinal flora in acute and chronic dextran sulfate sodium-induced colitis in mice

OBJECTIVE: There is increasing evidence that the intestinal microflora plays an important role in the pathogenesis of inflammatory bowel disease. In the present study, we examined the role of the resident intestinal flora in our model of dextran sulfate sodium (DSS)-induced acute and chronic colitis in mice. METHODS: Acute colitis was induced in BALB/c mice with 5% DSS in their drinking water for 7 days. Chronic colitis was established after four cycles of feeding 5% DSS for 7 days and water for 10 days. For eliminating intestinal bacteria, mice were injected intraperitoneally with metronidazole and ciprofloxacin. We analysed four parameters: (1) body weight, (2) length of the colon, (3) histological score, and (4) myeloperoxidase activity. RESULTS: In acute DSS colitis treatment with antibiotics led to an improvement of the histological parameters (epithelial damage, P< 0.05; inflammatory infiltrate, P< 0.05) and colon length (P < 0.0028). A significant reduction in granulocyte infiltration was indicated by a 52.6% reduced myeloperoxidase activity in colonic biopsies. By contrast, in chronic colitis, treatment of mice with antibiotics failed to show significant effects. CONCLUSION: In acute DSS-induced colitis bacteria and/or bacterial products play a major role in initiation of inflammation but not in chronic DSS colitis.     

己酮可可碱对小鼠TNBS结肠炎的药效学研究

目的观察己酮可可碱(PTX)对小鼠TNBS(三硝基苯磺酸)肠炎的作用.方法通过直肠给予雄性BALB/c小鼠TNBS诱导结肠炎,应用PIX对其进行治疗,6日后收集结肠标本评价结肠炎症程度.结果直肠内给予BALB/c小鼠TNBS后可造成小鼠结肠炎性改变:FTX治疗可使小鼠疾病活动指数、结肠重量和炎症指数均显著下降(P＜0.05).结论PTX治疗可使TNBS肠炎模型小鼠肠道炎症减轻.     

Peroxisome proliferator activated receptor gamma in colonic epithelial cells protects against experimental inflammatory bowel disease

INTRODUCTION: Peroxisome proliferator activated receptor gamma (PPARgamma) is expressed in epithelial cells, macrophage, and T and B lymphocytes. Ligand induced activation of PPARgamma was reported to attenuate colitis activity but it is not clear whether this protection is mediated by epithelial or leucocyte PPARgamma. METHODS: Mice with targeted disruption of the PPARgamma gene in intestinal epithelial cells, generated using a villin-Cre transgene and floxed PPARgamma allele and designated PPARgamma(DeltaIEpC), were compared with littermate mice having only the PPARgamma floxed allele with no Cre transgene that expressed PPARgamma in the gut, designated PPARgamma(F/F). Colitis was induced by administering dextran sodium sulphate (DSS) and the two mouse lines compared for typical symptoms of disease and expression of inflammatory cytokines. RESULTS: PPARgamma(DeltaIEpC) mice displayed reduced expression of the PPARgamma target genes ADRP and FABP in the gut but were otherwise normal. Increased susceptibility to DSS induced colitis, as defined by body weight loss, colon length, diarrhoea, bleeding score, and altered histology, was found in PPARgamma(DeltaIEpC) mice in comparison with PPARgamma(F/F) mice. Interleukin (IL)-6, IL-1beta, and tumour necrosis factor alpha mRNA levels in colons of PPARgamma(DeltaIEpC) mice treated with DSS were higher than in similarly treated PPARgamma(F/F) mice. The PPARgamma ligand rosiglitazone decreased the severity of DSS induced colitis and suppressed cytokine production in both PPARgamma(F/F) and PPARgamma(DeltaIEpC) mice. CONCLUSIONS: These studies reveal that PPARgamma expressed in the colonic epithelium has an endogenous role in protection against DSS induced colitis and that rosiglitazone may act through a PPARgamma independent pathway to suppress inflammation.     

丹参对右旋葡聚糖硫酸钠诱导小鼠结肠炎的疗效观察

目的 :评价丹参预防及治疗右旋葡聚糖硫酸钠 (DSS)结肠炎小鼠的有效性。方法 :2 0只正常小鼠随机分为两组 ,饮用 DSS7d,同时预防组用丹参 ,对照组用 0 .85 %氯化钠溶液。另 2 0只 DSS诱导的结肠炎小鼠随机分为两组 ,治疗组用丹参 ,对照组用 0 .85 %氯化钠溶液 7d。用疾病活动指数 (DAI)、组织学评分和马休斯猩红蓝(MSB)纤维素染色检测微血栓以评价疗效。结果 :丹参在预防组部分降低微血栓的形成 ,对照组 10例有 6例微血栓阳性 ,预防组 3例阳性。丹参治疗组与对照组的 DAI、直肠、横结肠组织学评分分别为 0 .4 5、0 .4 8(P>0 .0 5 ) ,1.36、1.76 (P<0 .0 5 ) ,1.35、1.6 0 (P<0 .0 5 )。结论 :丹参可能部分抑制微血栓形成和减轻 DSS结肠炎小鼠结肠炎症 ,提示丹参用于溃疡性结肠炎治疗也可能有效。     

葡聚糖硫酸钠自由饮用与定量灌胃诱导小鼠急性结肠炎模型的比较研究

背景：自由饮用葡聚糖硫酸钠（DSS）诱导的鼠类急性结肠炎模型均一性欠佳,动物死亡率较高。目的：评估2%DSS自由饮用或定量灌胃诱导的小鼠急性结肠炎模型模拟人类溃疡性结肠炎（UC）的效果和均一性。方法：予ICR小鼠2%DSS自由饮用或定量灌胃建立急性结肠炎模型,检测并比较正常对照组和两组模型小鼠的症状出现时间和频率、疾病活动指数（DAI）、DSS消耗量、死亡率、结肠长度、结肠损伤大体评分（MACD）、结肠组织病理学表现以及外周血白细胞计数和分类。结果：两组模型小鼠均出现类似人类UC的症状和组织病理学改变,结肠显著短缩,DAI、MACD以及外周血白细胞计数和中性粒细胞百分比显著高于正常对照组。与DSS自由饮用组相比,DSS定量灌胃组小鼠症状出现时间更为一致,症状出现率显著增高,动物死亡率和DSS消耗量显著减低。结论：2%DSS定量灌胃诱导的小鼠急性结肠炎模型能较稳定地模拟人类UC,均一性高,动物死亡率低。     

Evaluation of the effect of pyrrolidine dithiocarbamate in suppressing inflammation in mice with dextran sodium sulfate-induced colitis

AIM: To evaluate the effect of pyrrolidine dithio- carbamate (PDTC; an NF-κB inhibitor) administered at low (50 mg/kg) and high (100 mg/kg) doses in suppressing colitis in mice with dextran sodium sulfate (DSS)-induced colitis. METHODS: Mice were divided into a DSS-untreated group (normal group), DSS-treated control group, DSS+PDTC-treated groupⅠ(low-dose group), and DSS+PDTC-treated groupⅡ (high-dose group). In each group, the disease activity index score (DAI score), intestinal length, histological score, and the levels of activated NF-κB and inflammatory cytokines (IL-1β and TNF-α) in tissue were measured. RESULTS: The DSS+PDTC-treated groupⅡ exhibited suppression of shortening of intestinal length and reduction of DAI score. Activated NF-κB level and IL-1β and TNF-α levels were significantly lower in DSS+PDTC- treated groupⅡ. CONCLUSION: These findings suggest that PDTC is useful for the treatment of ulcerative colitis.     

趋化因子CCL20及其受体CCR6在实验性结肠炎小鼠中的表达及其意义

背景：溃疡性结肠炎（UC）的病因和发病机制尚不完全明确，趋化因子异常可能在其发生、发展中起重要作用。目的：研究趋化因子CCL20及其受体CCR6在葡聚糖硫酸钠（DSS）诱导的实验性结肠炎小鼠结肠黏膜中的表达以及CCL20与CCR6的相关性，探讨两者在结肠炎发病机制中的作用。方法：30只雌性BALB／c小鼠分为对照组和模型组。模型组小鼠自由饮用5％DSS溶液7d，建立实验性结肠炎模型；对照组小鼠自由饮用蒸馏水7d。第8d处死小鼠，观察疾病活动指数（DAI）、结肠组织学评分。以逆转录聚合酶链反应（RT．PCR）检测小鼠结肠黏膜CCL20、CCR6mRNA表达，以免疫组化和蛋白质印迹法检测结肠黏膜CCL20、CCR6蛋白表达，并分析CCL20与CCR6的相关性。结果：模型组DAI和结肠组织学评分均显著高于对照组（P〈0．01）；CCL20、CCR6mRNA和蛋白表达显著高于对照组（P〈0．01），且与结肠炎症程度呈正相关。CCL20mRNA表达与CCR6mRNA表达有明显相关性（r＝0．763．P=0．000071）。结论：CCL20和CCR6表达参与了结肠炎的发生和发展，两者相互作用可能在结肠炎局部结肠组织破坏和病理变化中起重要作用，有望成为UC的潜在治疗靶点。     

Prophylactic effect of Lactobacillus GG in animal colitis and its effect on cytokine secretion and mucin gene expressions]

BACKGROUND/AIMS: Lactobacillus rhamnosus GG (LGG) has been used in acute colitis treatment. However, it is unclear whether the LGG prevents chronic colitis. The aim of this study was to examine the prophylactic effect of LGG on animal colitis, cytokine secretion, and mucin gene expression. METHODS: BALB/c mice (n=64) were exposed to 5% dextran sulfate sodium (DSS) for 7 days followed by 10 days recovery period and repeatedly exposed for 4 days. Then, the mice were devided into three group; group of oral LGG adminstration throughout the recovery and repeated colitis period; PBS group of PBS administration; control group. Colon length, histologic score, tumor necrosis factor-alpha (TNF-alpha), interleukin-10 (IL-10) levels, mucin gene expressions were determined at each period. RESULTS: In acute colitis period, the LGG group showed higher levels of disease activity index (DAI), histologic score, TNF-alpha, IL-10, but shorter colon length, lower levels of mucin gene expressions than the control group. However, in repeated colitis period, the LGG group showed markedly lower levels of DAI and IL-10 but significantly longer colon length than PBS group (p<0.05). There was no difference in the mucin gene expression. CONCLUSIONS: These results suggest that LGG prevents chronic murine colitis. It may be associated with cytokine modulation and competitive inhibition of pathogenic bacteria. However, it may not be related with gene expression.