Effect of N-acetylcysteine on the Murine Model of Colitis Induced by Dextran Sodium Sulfate Through Up-Regulating PON1 Activity

Reactive oxygen species (ROS) are increased in inflammatory bowel disease (IBD) and have been implicated as mediators of intestinal inflammation. We investigated the hypothesis that N-acetylcysteine (NAC) as a glutathione (GSH) precursor attenuates disease progression in a murine dextran sodium sulfate (DSS)-induced colitis model. A colitis model was induced by adding 5% DSS into the drinking water for 7 days. BALB/c mice were injiciatur enema with saline, 5-ASA, N-acetylcysteine, respectively, and free drinking water as control group. DSS-treated mice developed severe colitis as shown by bloody diarrhea, weight loss, and pathologic involvement. Colon lengths were significantly decreased in DSS-treated mice with decreased GSH activity too (P < 0.01). ROS in the colon, the level of interleukin 1β (IL-1β) in colonic mucosa, serum tumor necrosis factor a (TNF-α), MPO, and MDA were significantly increased in DSS-treated animals (P < 0.01), with decreased PON1 activity (P < 0.01). However, NAC significantly decreased colonic MPO activity, ROS, TNF-α and IL-1β levels and increased PON1 activity and GSH concentration. Moreover, NAC attenuated the macroscopic colonic damage and the histopathologic changes-induced by DSS while similar to 5-ASA group. These results suggest that NAC may be effective in the treatment of colitis through its up-regulating PON1 and scavenging oxygen-derived free radicals.     

The intestinal anti-inflammatory activity of UR-12746S on reactivated experimental colitis is mediated through downregulation of cytokine production

BACKGROUND: UR-12746S (dersalazine sodium) is cleaved by colonic bacteria delivering the PAF antagonist UR-12715 and 5-ASA. This study describes the anti-inflammatory activity of UR-12746S in an experimental model of reactivated colitis and its effects on cytokine production. METHODS: Rats were initially rendered colitic by a colonic instillation of 10 mg of trinitrobenzenesulphonic acid (TNBS) dissolved in 0.25 ml of 50 % ethanol, and colitis was reactivated two weeks after by a second administration of the same dose of TNBS. Two groups of colitic rats received UR-12746S (25 and 50 mg/kg daily, p.o.) and colonic damage was evaluated every week for 4 weeks. Different biochemical markers of colonic inflammation were assayed: MPO activity and cytokine (IL-1beta and TNFalpha) levels. Also, the in vitro effects of UR-12715 and 5-ASA on cytokine production were assayed. RESULTS: UR-12746S showed anti-inflammatory effect in reactivated colitis in rats, as evidenced by a significant reduction in MPO activity. Both doses of UR-12746S decreased IL-1beta production, while only the highest dose assayed inhibited TNFalpha production. In vitro studies revealed that UR-12715 or 5-ASA (from 10(-6) to 10(-4) M) inhibited IL-8 production (30-40%) in HT-29 cells when incubated with LPS. This inhibitory effect was enhanced when both compounds were administered simultaneously at 10(-4) M. In addition, UR-12715 inhibited IL-1beta or TNFalpha production in THP-1 or U937 cells, respectively, when these cells were stimulated by PMA and LPS; whereas 5-ASA only showed a weak effect in inhibiting IL-1beta production. CONCLUSION: UR-12746S was able to prevent relapse in experimental colitis and inhibition of proinflammatory cytokine production participates in the intestinal anti-inflammatory activity exerted by this compound.     

Protective Effect of Lactulose on Dextran Sulfate Sodium-Induced Colonic Inflammation in Rats

Promising results have recently been obtained with pre- and probiotic therapy in ulcerative colitis (UC). The prebiotic potential of lactulose is well established, but it has not yet been investigated in experimental colitis models. The purpose of the study was to examine the effect of lactulose on an UC model induced by 3% dextran sulfate sodium (DSS) solution added to drinking water for 7 days in male Wistar rats. Lactulose (300-1000 mg/kg) or 5-aminosalicylic acid (5-ASA; 150 mg/kg) was administered orally twice daily for 6 days. Colonic ulceration area, colon length, body weight changes, diarrhea/bloody feces, colonic mucosal myeloperoxidase activity (MPO), thiobarbituric acid reactive substances (TBARS), and histology were examined. Treatment of animals with DSS for 7 days resulted in severe colonic lesions accompanied by diarrhea, bloody feces, a decrese in body weight, shortening of the colon length, and an increase in MPO activity as well as TBARS, compared to normal rats. Lactulose treatment ameliorated DSS-induced colitis in a dose-dependent manner, and at 1000 mg/kg all of the parameters examined, except TBARS, were shown to improve significantly as compared to controls. Daily administration of 5-ASA also significantly reduced the severity of colonic lesions following DSS treatment. These results demonstrated the protective effect of lactulose in this rat colitis model and suggested that the background of this lactulose effect may be due to alterations of colonic microflora.     

罗格列酮联合氨基水杨酸治疗溃疡性结肠炎

目的研究罗格列酮联合5-氨基水杨酸（ASA）对轻、中度活动期溃疡性结肠炎（UC）的疗效及相关细胞因子表达。方法参照2000年全国炎症性肠病学术研讨会制定的对炎症性肠病诊断治疗规范的建议,纳入2004年7—11月四川大学华西医院门诊确诊的慢性轻、中度活动期UC,1个月内未使用激素及免疫抑制剂的病例,排除感染性结肠炎、肠道阿米巴病、心肝肾功能不全者。治疗前后行血粪常规、肝肾功能、结肠镜检查。随机分为治疗组和对照组,均口服5-ASA 2g／d;治疗组加服罗格列酮4mg／d,临床观察期4周,4周后乙状结肠镜复查,进行疾病活动度、组织学评价,并观察治疗前后结肠上皮过氧化物酶增殖物激活受体γ（PPARγ）、NF-κB p65的表达。结果UC疾病活动指数积分在治疗组由平均5．87下降到1．86,完全缓解率为71．4％,部分缓解率为23．8％;对照组从6．05下降到2．57,完全缓解率为57．1％,部分缓解率为19．0％。组织学分级下降也高于对照组;PPARγ表达明显增加,NF—κB核阳性率明显降低,且两者之间有相关性。结论罗格列酮与5-ASA或柳氮磺吡啶联合应用较后者单独应用能够提高UC的治疗效果;UC时PPARγ表达降低,PPARγ配体可促进其表达增加;PPARγ缓解结肠炎症可能是通过抑制NF—κB活化完成,并可能代表UC治疗的一个新动向。     

复方黄柏液对大鼠TNBS结肠炎的治疗机制探讨

背景：临床上采用复方黄柏液保留灌肠辅助治疗溃疡性结肠炎（UC）疗效满意,但其作用机制尚不清楚。目的：探讨复方黄柏液对三硝基苯磺酸（TNBS）诱发的大鼠结肠炎模型炎症损伤的治疗作用及其可能机制。方法：40只成年雌性Sprague-Dawley大鼠随机分成四组,正常对照组不予处理,其余三组以TNBS／乙醇溶液灌肠制作结肠炎模型后．分别予0．9％NaCl溶液1ml、5-氨基水杨酸（5-ASA）200mg／kg和复方黄柏液1ml灌肠,连续14d。治疗后评估大鼠疾病活动指数（DAI）以及结肠大体、组织学损伤情况;检测结肠组织髓过氧化物酶（MPO）活性和白三烯B4（LTB4）含量;心脏采血,流式细胞术检测中性粒细胞凋亡率。结果：与正常对照组相比,TNBS模型组DAI、结肠大体和组织学评分、结肠组织MPO活性和LTB。含量均显著升高,血中性粒细胞凋亡率显著降低（P〈0．01）;5-ASA治疗组和复方黄柏液治疗组上述指标均较TNBS模型组显著改善（P〈0．01）,两组间差异则无统计学意义。结论：复方黄柏液灌肠对大鼠TNBS结肠炎具有明显治疗作用,促进中性粒细胞凋亡、清除结肠局部损伤因子（MPO、LTB。）可能为其作用机制之一。     

5-ASA and lycopene decrease the oxidative stress and inflammation induced by iron in rats with colitis

Background Supplementation of 5-aminosalicylic acid (5-ASA) and of iron are among the principal therapies in patients with inflammatory bowel disease. Therapeutic iron, as well as heme iron from chronic mucosal bleeding, can increase iron-mediated oxidative stress in colitis. This study was designed to examine the influence of iron supplementation on histological expression and oxidative status relative to 5-ASA treatment and antioxidant treatment.Methods Colitis was induced using the iodoacetamide rat model, and rats were divided into different dietary groups of 6 rats each: 1, normal chow diet (control); 2, diet supplemented with iron; 3, iron supplementation and lycopene; 4, iron and -carotene; 5, 5-ASA; 6, 5-ASA and lycopene; 7, 5-ASA and iron; 8, 5-ASA, iron, and lycopene. The animals were killed after 3 days and the weight of the ulcerated area recorded. Mucosal specimens were histologically evaluated. Myeloperoxidase (MPO) was measured to evaluate inflammatory status (U/g). Malondialdehyde (MDA) was measured in colonic tissue (µmol/g) and superoxide dismutase (SOD) in erythrocytes to assess the degree of tissue oxidative stress.Results Significantly more severe colitis, including necrosis, ulceration, and hemorrhage, was seen in colonic biopsies of rats with colitis when iron was supplemented. This pathology was attenuated when iron was given in combination with 5-ASA and/or lycopene. There was no significant benefit from adding -carotene.Conclusions Iron supplementation can amplify the inflammatory response and subsequent mucosal damage in a rat model of colitis. We suggest that the resultant oxidative stress generated by iron supplementation leads to the extension and propagation of crypt abscesses, either through direct membrane disruption by lipid peroxidation or through the generation of secondary toxic oxidants. Simultaneous treatment with 5-ASA and/or lycopene minimizes the potential hazard of iron. Therefore, we suggest giving iron supplementation with 5-ASA or lycopene or both.     

益生菌VSL#3对实验性结肠炎大鼠结肠黏膜Claudins蛋白表达的影响

目的 观察益生菌VSL#3对2,4,6-三硝基苯磺酸(TNBS)诱导的大鼠急性结肠炎的保护作用,以及对紧密连接蛋白Claudins（Claudin-1,-2,-3）在结肠黏膜上表达的影响。方法 24只健康雌性SD大鼠采用TNBS一次性灌肠法建立大鼠结肠炎模型,造模完成后第2天开始,8只大鼠每日给予2ml0.9％ NaC1溶液灌胃（TNBS组）,8只给予100 mg VSL#3（VSL#3组）,另8只给予200 mg 5-氨基水杨酸(5-ASA)灌胃（5-ASA组）。5只同级别未造模大鼠作为对照组每日给予0.9％ NaCl溶液灌胃,均持续1周并处死。处死时留取粪便标本并做细菌培养以检测肠道菌群的变化。通过观察腹泻、便血和体重情况计算疾病活动指数(DAI)。取结肠组织做HE染色,观察病理学改变;酶联免疫吸附试验(ELISA)检测肠组织髓过氧化物酶(MPO)的变化;量子点免疫荧光标记法检测Claudins在结肠黏膜的表达和分布。结果 与TNBS组比较,益生菌VSL#3和5-ASA治疗均能降低结肠炎大鼠明显升高的DAI和肠组织MPO水平,减轻结肠炎性反应评分。与对照组比较,结肠炎大鼠的肠道细菌计数发生改变,Claudin-1,-2,-3蛋白表达均明显增加（平均荧光强度分别为66.200±5.737、71.780±6.670、61:300土5.199,t值分别＝17.237、27.909和21.788;P值均＜0.01）;而与TNBS组和5-ASA组比较,VSL#3可调节肠道菌群平衡,增加Claudin-1,-3的表达（Claudin-1:75.550±8.717比66.200±5.737和67.080±5.401;t＝9.348,8.469;P值均＜0.05;Claudin-3:68.820±7.443比61.300土5.199和59.830±5.930;t＝7.519,8.988,P值均＜0.05),降低Claudin-2的表达(58.740±6.457比71.780±6.670和66.870±5.791;t＝13.033,P＜0.01;t＝8.123,P＜0.05)。结论 益生菌VSL#3可能通过改变Claudins蛋白的表达,增强肠黏膜屏障功能,从而发挥缓解急性结肠炎性反应的作用。     

Protective effect of angelica sinensis polysaccharide on experimental immunological colon injury in rats

AIM: To study the effect of angelica sinensis polysaccharide (ASP) on immunological colon injury and its mechanisms in rats.METHODS: Immunological colitis model of rats was induced by intracolon enema with 2, 4, 6-trinitrobenzene sulfonic acid (TNBS) and ethanol. The experimental animals were randomly divided into normal control, model control, 5-aminosalicylic acid therapy groups and three doses of ASP therapy groups. The 6 groups were treated intracolonically with normal saline, normal saline, 5-aminosalicylic acid (100 mg.kg-1), and ASP daily (8:00 am) at the doses of 200, 400 and 800 mg.kg-1 respectively for 21 days 7 d following induction of colitis. The rat colon mucosa damage index (CMDI), the histopathological score (HS), the score of occult blood test (OBT), and the colonic MPO activity were evaluated. The levels of SOD, MDA, NO, TNF-α, IL-2 and IL-10 in colonic tissues were detected biochemically and immunoradiometrically. The expressions of TGF-β and EGF in colonic tissues were also determined immunochemically.RESULTS: Enhanced colonic mucosal injury, inflammatory response and oxidative stress were observed in colitis rats,which manifested as significant increases of CMDI, HS, OBT,MPO activity, MDA and NO contents, as well as the levels of TNF-α and IL-2 in colonic tissues, although colonic TGF-β protein expression, SOD activity and TL-10 content were significantly decreased compared with the normal control (P＜0.01). However, these parameters were found to be significantly ameliorated in colitis rats treated intracolicly with ASP at the doses of 400 and 800 mg@kg-1 (P＜0.05-0.01).Meantime, colonic EGF protein expression in colitis rats was remarkably up-regulated.CONCLUSION: ASP has a protective effect on immunological colon injury induced by TNBS and ethanol enema in rats,which was propably due to the mechanism of antioxidation,immunomodulation and promotion of wound repair.     

4-氨基水杨酸对大鼠实验性结肠炎中性粒细胞趋化、活化及凋亡的影响

目的 观察4-氨基水杨酸(4-ASA)对三硝基苯磺酸(TNBS)诱导的大鼠实验性结肠炎炎症损伤、肠组织一氧化氮合酶(iNOS)表达、血中性粒细胞(PMN)凋亡及血清白细胞介素(IL)-8水平等的影响,探讨4-ASA对炎症性肠病(IBD)的治疗作用及机制.方法 40只SD大鼠分为正常对照组(n=10)和实验组(n=30),实验组建立大鼠结肠炎模型.建模第5天将实验组按照处理方式分为实验对照组(n=10,0.9%氯化钠1 ml灌肠),5-ASA组[n=10,5-ASA液(200 mg/kg)1 ml灌肠]和4-ASA组[n=10,4-ASA液(200 mg/kg)1 ml灌肠].连续治疗7 d后处死动物,取病变段肠组织,行结肠大体损伤及结肠组织学损伤评分;生化法检测髓过氧化物酶活性;免疫组化法检测肠组织iNOS表达量;流式细胞术检测血PMN凋亡率;酶联免疫吸附法检测血清IL-8浓度.结果 经4-ASA治疗7d后,4-ASA组大鼠体重明显较实验对照组增加(P<0.01,t=14.09);疾病活动指数评分、大体评分、组织学评分和MPO活性显著较实验对照组降低(t值分别=7.87、18.37、6.66和19.60,P值均<0.01).而5-ASA组与4-ASA组间上述各指标差异均无统计学意义(P值均>0.05).实验对照组肠组织iNOS表达率为(73.55±5.15)%,较正常对照组显著增加[(5.95±1.45)%,t=39.93,P<0.01)];5-ASA和4-AsA组大鼠肠组织iNOS表达率分别为(37.80±3.82)%和(42.27±3.52)%,均较实验对照组显著降低(t值分别=17.62和15.76,P值均<0.01).实验对照组血清IL-8的平均浓度明显高于正常对照组(t=25.25,P<0.01);5-ASA和4-ASA组明显低于实验对照组(t值分别=12.31和11.57,P值均<0.01).实验对照组血PMN凋亡率明显低于正常对照组(t=11.48,P<0.01);5-ASA和4-ASA组凋亡率明显高于实验对照组(t值分别=7.51和10.47,P值均<0.01).结论 4-ASA灌肠对实验性结肠炎大鼠具有显著的治疗作用,其治疗机制可能与降低PMN的趋化与激活、上调血PMN凋亡率、减少肠组织局部损伤因子有关.     

Measurement of colonic mucosal concentrations of 5-aminosalicylic acid is useful for estimating its therapeutic efficacy in distal ulcerative colitis: comparison of orally administered mesalamine and sulfasalazine

OBJECTIVES: Oral 5-aminosalicylic acid (5-ASA) preparations have been used frequently in the treatment of ulcerative colitis. However, there have been few reports investigating the relationship between colonic mucosal concentrations of 5-ASA and its clinical efficacy when oral sulfasalazine or 5-ASA compounds were administered. The aim of this study is to compare the mucosal concentrations of 5-ASA ensured by sulfasalazine or mesalamine, and to define the clinical significance of the measurement of 5-ASA concentrations in the treatment of distal ulcerative colitis. MATERIALS AND METHODS: Biopsies were taken from the rectum and sigmoid colon of the oral sulfasalazine group (n = 13) and the slow-release 5-ASA (mesalamine) group with (n = 5) or without (n = 11) rectal administration of 5-ASA. High-pressure liquid chromatography was used to measure the tissue concentrations of 5-ASA and its metabolites. We compared the 5-ASA concentrations of the sulfasalazine group with the mesalamine group. Furthermore, we analyzed the relationship between tissue 5-ASA concentrations and the Disease Activity Index (DAI). RESULTS: The concentrations of 5-ASA and acetyl-5-ASA in the sulfasalazine group were higher than those in the group taking oral mesalamine alone (p < 0.01). The concentration of 5-ASA was much higher in the patients who received oral and rectal mesalamine in an enema than in the patients who had oral mesalamine alone. There was a significant inverse correlation between the DAI and concentrations of 5-ASA in the rectum (r = 0.712, p < 0.001). CONCLUSIONS: We demonstrated that the colonic mucosal concentration of 5-ASA was significantly higher in the sulfasalazine group than in the mesalamine group. Furthermore, the concentrations of mucosal 5-ASA may be a good marker for the estimation of its efficacy in the treatment of ulcerative colitis.     

Acetic acid-derived prostaglandin-dependent colonic adaptive cytoprotection is preserved in chronic colitis: role of cyclo-oxygenase

BACKGROUND AND AIMS: We recently reported the phenomenon of prostaglandin-dependent colonic adaptive cytoprotection (CAP) against acute colonic injury induced by acetic acid (AA) in the normal colon. This study investigated whether the CAP is preserved in the chronic inflamed colon. MATERIALS AND METHODS: Normal rats and a chronic colitis model, induced by trinitrobenzene sulfonic acid, received an intracolonal administration (0.5 ml) of saline or AA at low concentration (1%) followed by high concentration (8%) 30 min later. The distal colon was removed 48 h after 8% AA administration, and colitis was assessed by macroscopic scoring and measurement of the myeloperoxidase (MPO) activity. Indomethacin (5 mg/kg), a nonselective cyclo-oxygenase (COX) inhibitor, or N-[2-cyclohexyloxy-4-nitrophenyl] methane-sulfonamide (NS398, 1 mg/kg), a COX type 2 selective inhibitor, was injected intraperitoneally 1 h before pretreatment with 1% AA. RESULTS: Intracolonal administration of 8% AA induced colonic mucosal damage (macroscopic score 10.0+/-0.9) and elevated MPO activity (2.8+/-0.2 U/g), which were significantly reduced to 3.3+/-0.8 and 1.8+/-0.2 U/g by 1% AA pretreatment, respectively. Indomethacin abolished the gross mucosal protective effect by 1% AA pretreatment in 8% AA-derived colitis in normal rats while the NS398 had no effect. Both indomethacin and NS398 reversed the MPO activity reduction induced by 1% AA pretreatment. In chronic inflamed colon 8% AA treatment resulted in an increase in the macroscopic score to 11.5+/-0.4 from 4.7+/-0.4, but not the MPO activity, which was significantly reduced to 5.7+/-0.9 by 1% AA pretreatment. This gross mucosal protective effect by 1% AA pretreatment in chronic inflamed colon was reversed by indomethacin while the NS398 had no effect. CONCLUSION: These data show that COX-1 and COX-2 derived prostaglandins induced by low concentration AA pretreatment reduce the colonic mucosal injury and the increase in the MPO activity in colitis, respectively. The protective effect of COX-1 is preserved in chronic inflamed colon. These findings support the existence of a low concentration of AA-derived prostaglandin-dependent CAP and suggest that colonic AA, which is derived from bacterial breakdown of carbohydrate and protein in the colon, plays a crucial role in the endogenous defense mechanisms.     

Anti-tryptase treatment using nafamostat mesilate has a therapeutic effect on experimental colitis

OBJECTIVE: Mast cell tryptase has been proposed to be involved in the pathogenesis of human inflammatory bowel disease (IBD). Recently, it was reported that a low dose of nafamostat mesilate (NM), a serine protease inhibitor that is widely used to treat disseminated intravascular coagulation (DIC) and acute pancreatitis, can selectively inhibit human tryptase activity. The aim of this study was to investigate the anti-inflammatory effects of NM on experimental colitis in rats. MATERIAL AND METHODS: Colitis was induced in male Wistar rats using an enema of trinitrobenzene sulfonic acid (TNBS) dissolved in 50% ethanol. NM or 5-aminosalicylic acid (5-ASA), foundation therapy for mild-to-moderate IBD, was administered via the anus once a day on each of the 6 days after administration of TNBS. Colonic inflammation was assessed 1 week after TNBS administration. RESULTS: Intracolonic administration of TNBS resulted in the infiltration of numerous tryptase-positive cells in the colonic mucosa. The colonic mucosal injury induced by TNBS was significantly decreased by treatment with NM or 5-ASA. The increases in thiobarbituric acid-reactive substances (TBA-RS), myeloperoxidase (MPO) activity, tumor necrosis factor (TNF)-alpha and cytokine-induced neutrophil chemoattractants-1 (CINC-1) in the colonic mucosa were inhibited in the NM group and the 5-ASA group, without significant differences between them. CONCLUSIONS: These results indicate that a low dose of NM can inhibit the colonic mucosal inflammation induced by TNBS in rats, which suggests that anti-tryptase therapy using low doses of NM has excellent potential to become a new therapeutic strategy for IBD.     

Neonatal maternal deprivation triggers long term alterations in colonic epithelial barrier and mucosal immunity in rats

BACKGROUND: Stressful events in the early period of life (for example, maternal deprivation) have been shown to modify adult immune and gastrointestinal tract functions. The present study aimed to establish whether maternal deprivation affects colonic epithelial barrier and the development of an experimental colitis in adult rats. METHODS: Male Wistar rat pups were separated during postnatal days 2-14 or left undisturbed with their dam. At 12 weeks of age, we assessed colonic paracellular permeability, bacterial translocation, myeloperoxidase (MPO) activity, mucosal mast cell density, cytokine (interleukin (IL)-1 beta, IL-2, IL-4, IL-10, and interferon gamma (IFN-gamma)) mRNA expression, and macroscopic damage. Total gut permeability, MPO activity, and macroscopic damage were also assessed four days after intracolonic administration of 2,4,6-trinitrobenzenesulphonic acid (TNBS). RESULTS: Maternal deprivation triggered a significant increase in colonic permeability associated with bacterial translocation into the mesenteric lymph nodes, liver, and spleen. These alterations were associated with some macroscopic damage and an increase in colonic MPO activity, mucosal mast cell density, and cytokine mRNA expression. Intracolonic infusion of TNBS induced a significantly higher inflammatory reaction in separated animals, as judged by enhanced MPO colonic levels, total gut permeability, and macroscopic lesions. CONCLUSIONS: Maternal deprivation promotes long term alterations in the colonic epithelial barrier associated with an exaggerated immune response to an external immune stimulus. This suggests a role for early psychological factors in the regulation of colonic mucosal barrier in later life.     

MUC Genes Are Differently Expressed During Onset and Maintenance of Inflammation in Dextran Sodium Sulfate-Treated Mice

Colonic mucosal protection is provided by mucous gel, mainly composed of secreted (Muc2) and membrane-bound (Muc1, Muc3, Muc4) mucins. Our aim was to determine the expression profile of secreted and membrane-bound mucins in experimental dextran sulfate sodium (DSS)-induced colitis. Acute colitis was induced in Balb/C mice by oral administration of 1.0% DSS (5 days) and chronic colitis was maintained by subsequent 0.15% DSS treatment (28 days). Clinical symptoms (mortality, weight gain), stool scores, and MPO activity confirmed the inflammatory state in the two phases of colitis. Muc2 gene expression was not modified by colitis, whereas Muc3 gene expression was increased (×2) only in the cecum and the distal colon of mice after acute colitis. Muc1 and Muc4 mRNA levels were more significantly increased in the cecum (×8–10) than in colonic segments (×4) after acute colitis. TFF3 involved in mucosal repair was up-regulated during colitis induction. These results indicate that Muc and TFF3 genes are regulated early in inflammation and suggest that their mRNA levels could be used as early markers of inflammation.     

Effect of aminophenols (5-ASA and 4-ASA) on colonic interleukin-1 generation.

The effect of 5-ASA and 4-ASA, drugs used for the treatment of inflammatory bowel disease, on modulation of experimental colitis and on colonic generation of interleukin-1 was evaluated. Three weeks of treatment with 5-ASA or 4-ASA (50 micrograms/kg) and one week of treatment with 5-ASA significantly decreased colonic interleukin-1 generation and the extent and severity of inflammation in a rat model of colitis induced by trinitrobenzene sulphonic acid. Colonic biopsies were obtained from patients with active ulcerative colitis and organ cultured 24 hours in the absence or presence of the following drugs: sulphasalazine, sulphapyridine, 5-ASA and 4-ASA (25-100 micrograms/ml). Interleukin-1 content in tissue cultured in the presence of 5-ASA (100 micrograms/ml) was two-thirds of its content in tissue cultured in drug free medium and its release into the medium was decreased by 50%. Sulphasalazine 50 micrograms/ml significantly decreased by 33% the tissue content but did not affect interleukin-1 release and a higher dose was not more effective. Sulphapyridine and 4-ASA in doses up to 100 micrograms/ml did not affect either interleukin-1 colonic content or its release into the culture medium. We conclude that pharmacological suppression of colonic interleukin-1 generation may be one, although not the sole mechanism to explain the therapeutic efficacy of 5-ASA in the treatment of inflammatory bowel disease.     

吉法酯对三硝基苯磺酸诱导大鼠实验性结肠炎的作用

目的 观察吉法酯对三硝基苯磺酸(TNBS)诱导的大鼠实验性结肠炎髓过氧化物酶(MPO)、环氧合酶(COX)-1及COX-2表达的影响,探讨吉法酯对溃疡性结肠炎的治疗作用.方法 选用雌性健康SD大鼠40只,均分为A、B、C、D组.A、B、C三组大鼠采用TNBS/乙醇灌肠制作大鼠结肠炎模型.造模后第2天,A组每天给予0.9%氯化钠溶液1 ml灌肠;B组每天给予5-氨基水杨酸(5-ASA)1 ml灌肠(100 mg/kg);C组每天给予吉法酯1 ml灌胃.D组为正常对照组.分别于造模后第7天及第14天每组处死5只大鼠,按疾病活动指数(DAI)的评分标准进行大体损伤评分,HE染色进行组织损伤评分.同时取结肠病变部位组织,生化法检测MPO活性,免疫组化法检测COX-1与COX-2的组织表达.结果 与A组比较,B组和C组的DAI评分、大体损伤形态和组织学损伤评分及MPO活性均降低(P<0.05).与A组相比,B、C、D组第7天和第14天COX-1表达水平升高(P<0.05),分别为0.87±0.18和0.93±0.15比1.86±0.51和1.96±0.41,1.73±0.68和1.79±0.6以及1.91±0.34和1.99±0.45;COX-2水平降低(P<0.05),分别为3.50±0.23和3.06±0.27比1.53±0.19和0.73±0.15,1.73±0.94和0.86±0.29,0.24±0.18和0.18±0.16.D组COX-2表达极弱,与B、C两组间差异有统计学意义(P<0.05).结论 吉法酯对TNBS诱导的大鼠结肠炎有较好的治疗作用,其疗效与5-ASA相似,其作用机制可能是降低肠组织中MPO的活性和调节COX-1/COX-2表达.     

The Effect of Melatonin on TNBS-Induced Colitis

Ulcerative colitis is a multifactorial inflammatory disease of the colon and rectum with an unknown etiology. The present study was undertaken to investigate the effect of melatonin administration on oxidative damage and apoptosis in 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis. Rats were divided into four groups as follows: Group 1 (n=8)—TNBS colitis; Group 2 (n=8)—melatonin, 10 mg/kg/day ip, for 15 days in addition to TNBS; Group 3 (n=8)—melatonin alone, 10 mg/kg/day ip, for 15 days; and Group 4 (n=8)—isotonic saline solution, 1ml/rat ip, for 15 days (sham control group). Colonic myeloperoxidase (MPO) activities, malondialdehyde (MDA) levels, and glutathione (GSH) levels are indicators of oxidative damage, while caspase-3 activities reveal the degree of apoptosis of the colonic tissue. In all TNBS-treated rats, colonic MPO activity and MDA levels were found to be increased significantly compared to those in the sham group. Colonic MPO activity and MDA levels were significantly lower in the melatonin treatment group compared to TNBS-treated rats. GSH levels of colonic tissues were found to be significantly lower in TNBS-treated rats compared to the sham group. Treatment with melatonin significantly increased GSH levels compared to those in TNBS-treated rats. Caspas-3 activity of colonic tissues was found to be significantly higher in TNBS-treated rats compared to the sham group. Treatment with melatonin significantly decreased caspase-3 activity compared to that in TNBS-treated rats. These results imply a reduction in mucosal damage due to anti-inflammatory and anti-apoptotic effects of melatonin.     

Hyperbaric Oxygen Therapy Is as Effective as Dexamethasone in the Treatment of TNBS-E-Induced Experimental Colitis

Introduction Hyperbaric oxygen (HBO) has been demonstrated to be useful as an adjunctive therapy for Crohn’s disease. In the present study, HBO was tested as a treatment for trinitrobenzenesulfonic acid–ethanol (TNBS-E)-induced distal colitis, and its effects were compared with dexamethasone therapy. Methods A total of 48 Sprague-Dawley rats were separated into six groups: the control, and those treated with vehicle, TNBS-E, HBO, dexamethasone, or combined HBO + dexamethasone. The HBO treatment group was exposed to 100% HBO at 2 ATM for 75 min twice daily at 6-h intervals in a HBO chamber, both on the day of colitis induction and 3 days thereafter. Treatment with intraperitoneal dexamethasone twice daily was started 1 h before the induction of colitis and was continued for 7 days in the dexamethasone group. The rats were decapitated 8 days after the induction of colitis, and the colonic tissue wet weight, macroscopic and microscopic lesion score, and tissue myeloperoxidase (MPO) activity were determined. Results HBO therapy decreased the activity of experimental colitis measured by the tissue wet weight, macroscopic score, microscopic score, and MPO activity. The dexamethasone treatment significantly reduced the colitis activity as determined by the tissue MPO activity and wet weight. There were also decreases in the macroscopic and microscopic activity scores with the dexamethasone therapy; however, these changes were not statistically significant. The combined therapy with HBO and dexamethasone provided no additional benefit over HBO therapy alone. Conclusion HBO therapy can be a valuable therapeutic option in treatment of patients with inflammatory bowel disease. HBO therapy in the refractory patients deserves further, larger clinical studies.     

Rebamipide Enema is Effective for Treatment of Experimental Dextran Sulfate Sodium Induced Colitis in Rats

We investigated therapeutic efficacy of rebamipide using dextran sulfate sodium (DSS) induced colitis model in rats. Three percent DSS solution was given to rats for 9 days. After that, we evaluated the drug efficacy on colitis sustained with continuous drinking of 1% DSS. Twice-daily treatment with 0.3% or 1% rebamipide for 14 days significantly ameliorated the stool abnormality in the colitis model, preferentially suppressed hematochezia. The colonic mucosal lesion, determined by Alcian blue staining on day 24, was significantly reduced by rebamipide enema in a dose-dependent manner. Either rebamipide or 5-aminosalycilic acid (5-ASA) enema treated once daily significantly ameliorated colitis. The minimum effective dose of rebamipide was 0.3% in once-daily treatment, and that of 5-ASA was 10%. In a mechanistic study, the epithelial cell sheet formation of the T84 colon cancer cell was measured as an increase in generation of trans-epithelial electrical resistance in vitro. Rebamipide accelerated the increase, while 5-ASA conversely suppressed it. These results suggest that rebamipide enema is effective for treatment of experimental ulcerative colitis (UC).