紫甘薯花青素对DSS诱导的溃疡性结肠炎小鼠肠道屏障损伤的修复作用

目的:探究紫甘薯花青素对葡聚糖硫酸钠(DSS)诱导的溃疡性结肠炎小鼠肠道屏障损伤的修复及治疗作用。方法:将健康雄性BALB/c小鼠分正常饮水组、DSS模型组、紫甘薯花青素不同剂量(12.5、25、50及75mg/kg)组和5-氨基水杨酸(5-ASA)阳性药物对照组。口服含2.5%DSS的饮用水建立小鼠溃疡性结肠炎模型。免疫组织化学技术检测小鼠结肠中紧密连接蛋白ZO-1和occludin以及炎症因子肿瘤坏死因子α(TNF-α)和白细胞介素6(IL-6)的表达。糖原PAS染色技术观察结肠组织杯状细胞中黏液素的表达的情况,Western blot检测ZO-1、occludin和TNF-α的蛋白表达,天狼星红染色技术检测小鼠结肠纤维化情况。结果:与正常饮水对照组相比,DSS模型小鼠疾病活动指数,组织学损伤明显增加(P0.01);与DSS模型组相比,紫甘薯花青素不同剂量组小鼠的疾病活动指数评分降低,结肠组织中ZO-1和occludin的表达及分布均上升,且TNF-α和IL-6的表达及分布均下降;糖原PAS色显示结肠组织杯状细胞中的黏液素分布及表达在紫甘薯花青素治疗组明显增加;天狼星红染色也显示,紫甘薯花青素治疗组小鼠结肠纤维化程度较模型组降低。结论:紫甘薯花青素具有治疗DSS诱导的小鼠溃疡性结肠炎的作用,其主要通过上调紧密连接蛋白ZO-1和occludin的表达,保护肠道屏障的完整性,同时抑制炎症因子TNF-α和IL-6的表达以及肠道纤维化,来抑制结肠炎症的发展。     

基于NF-κB/NLRP3/caspase-1通路研究白及多糖对溃疡性结肠炎大鼠肠黏膜炎症损伤的保护作用北大核心CSCD

目的:探究白及多糖对溃疡性结肠炎(UC)大鼠核因子κB(NF-κB)/核苷酸结合寡聚化结构域样受体蛋白3(NLRP3)/半胱天冬酶-1(caspase-1)通路蛋白表达及对肠道屏障损伤的影响。方法:采用三硝基苯磺酸(TNBS)+乙醇法建立UC模型,并将SD大鼠随机分为空白组、模型组、白及多糖低(100 mg/kg)、中(200 mg/kg)、高(400 mg/kg)剂量组、柳氮磺胺吡啶阳性组(0.67 g/kg),除空白组外,其余各组均建立UC模型。白及多糖低、中、高剂量组和阳性组分别灌胃给予相应剂量白及多糖和柳氮磺胺吡啶,空白组和模型组灌胃给予10 ml/kg生理盐水,各组大鼠连续给药2周,1次/d。末次给药12 h后,观察大鼠一般行为并对大鼠进行疾病活动指数(DAI)评分;取大鼠结肠组织,苏木精-伊红染色观察组织病理形态;ELISA检测结肠组织髓过氧化物酶(MPO)、炎症因子IL-1β、肿瘤坏死因子-α(TNF-α)水平及肠道屏障功能受损指标二胺氧化酶(DAO)和肠型脂肪酸结合蛋白(i-FABP)水平;Western blot检测结肠组织通路蛋白NF-κB p65、磷酸化NF-κB p65(p-NF-κB p65)、NLRP3、caspase-1、cleaved caspase-1蛋白表达。结果:与空白组比较,模型组大鼠形体消瘦、大便稀溏、结肠组织可见黏膜溃疡、充血、扩张及炎症细胞浸润等病理损伤,DAI评分、结肠组织MPO、IL-1β及TNF-α含量、p-NF-κB p65/NF-κB p65、NLRP3、caspase-1、cleaved caspase-1蛋白表达均升高(P<0.05),DAO和i-FABP含量均降低(P<0.05)。与模型组比较,白及多糖各剂量组及柳氮磺胺吡啶组大鼠DAI评分、结肠组织病理损伤程度、MPO、IL-1β及TNF-α含量、p-NF-κB p65/NF-κB p65、NLRP3、caspase-1、cleaved caspase-1蛋白表达均降低(P<0.05),DAO和i-FABP含量均升高(P<0.05),且呈剂量依赖性,高剂量白及多糖改善效果与柳氮磺胺吡啶相近(P>0.05)。结论:白及多糖可抑制NF-κB/NLRP3/caspase-1通路激活,降低炎症反应和肠屏障损伤,改善UC症状和肠黏膜损伤。     

白芨多糖上调溃疡性结肠炎小鼠肠黏膜紧密连接蛋白occludin的表达

目的探讨白芨多糖(BSP)对葡聚糖硫酸钠(DSS)诱导的溃疡性结肠炎(UC)小鼠的作用及其对肠黏膜紧密连接occludin蛋白的影响。方法将小鼠随机分为对照组、DSS模型组(自由饮用2.5%DSS溶液7 d)、柳氮磺吡啶(300 mg/kg)阳性对照组以及BSP低(125 mg/kg)和高(250 mg/kg)剂量组。均从建模开始灌胃给药,1次/d,连续7 d。观察小鼠的体质量变化、疾病活动指数(DAI)评分、组织病理学评分及结肠长度等炎性反应,Western blot检测结肠组织occludin蛋白的表达。结果与对照组比较,DSS模型组小鼠体质量显著减轻,结肠缩短,DAI评分和组织病理学评分显著升高(P0.01);结肠组织occludin蛋白的表达显著减少(P0.01)。与DSS模型组比较,BSP能够显著改善UC小鼠体质量减轻和结肠缩短,降低DAI评分和组织病理学评分,上调结肠组织occludin蛋白的表达。结论 BSP可以减轻DSS诱导的UC小鼠的结肠炎性反应,其作用机制可能与其上调肠黏膜occludin蛋白的表达,从而保护肠上皮屏障有关。     

蒙花苷对溃疡性结肠炎小鼠肠黏膜屏障的影响

目的 探讨蒙花苷（linarin,LN）对溃疡性结肠炎（ulcerative colitis,UC）小鼠肠黏膜屏障功能的影响及其相关机制。方法 采用3%右旋葡聚糖硫酸钠（dextran sodium sulfate,DSS）饮用法制作UC小鼠模型,将造模成功的小鼠分为模型组（Model）、柳氮磺吡啶组（SASP）、蒙花苷低剂量组（L-LN）、蒙花苷中剂量组（M-LN）和蒙花苷高剂量组（H-LN）,另设置正常对照组（Control）,连续灌胃给药7 d。评估小鼠疾病活动指数（disease activity index,DAI）评分;HE染色观察结肠组织病理学变化;测定肠道黏膜通透性（以尿液中的乳果糖和甘露醇的比值表示,即L/M值）;采用ELISA法测定结肠组织炎症因子IL-1β、TNF-α及IL-6及血清中黏膜屏障通透性标志物D-乳酸（D-lactic acid,D-LA）和二胺氧化酶（diamine oxidase,DAO）水平;Western blot检测小鼠结肠组织中紧密连接蛋白ZO-1、Occludin和TLR4/NF-κB信号通路相关蛋白TLR4,NF-κBp65、NF-κB...     

调补肺肾三法对慢性阻塞性肺疾病稳定期大鼠肠道黏膜屏障的影响

目的：探讨调补肺肾三法对慢性阻塞性肺疾病(COPD)稳定期大鼠肠道黏膜屏障的作用。方法：将SPF级SD大鼠随机分为空白(control)组、COPD模型(model)组、补肺健脾(BJ)组、补肺益肾(BY)组、益气滋肾(ZS)组和茶碱(Am)组。于第1～8周采用香烟烟雾暴露联合脂多糖滴注法制备COPD稳定期大鼠模型，第9～12周分别给予各组大鼠灌胃。观察动物一般情况，HE染色观察肺和结肠组织形态学变化，透射电镜下观察结肠组织超微结构变化，TUNEL法测定结肠组织细胞凋亡率，免疫组化染色检测结肠组织occludin (OCLN)和zonula occludens-1(ZO-1)蛋白表达，ELISA法检测血清二胺氧化酶(DAO)、肠脂肪酸结合蛋白(IFABP)和D-乳酸(D-LA)水平。结果：与control组比较，model组大鼠出现进食减少、消瘦和大便溏薄等症状，支气管黏膜皱襞增多明显，肺泡结构紊乱，形成大的气腔，大量炎症细胞浸润；结肠黏膜结构破坏，大量上皮细胞坏死脱落，杯状细胞明显减少，吸收上皮细胞的微绒毛稀疏、缺损，细胞间隙增宽，细胞间连接装置损坏，结肠细胞凋亡率显著升高(P<...     

柚皮素通过miR-22抑制NLRP3炎症小体并减轻溃疡性结肠炎大鼠模型肠屏障损伤

目的:探究柚皮素通过调控微小RNA-22(miR-22)的表达,对溃疡性结肠炎(UC)大鼠NLRP3炎症小体的影响以及对肠屏障的保护作用。方法:将SD雄性大鼠随机分成对照组、模型组、低剂量柚皮素组、高剂量柚皮素组和柚皮素+miR-22 antagomiR组,每组10只。除对照组外,其余各组大鼠使用葡聚糖硫酸钠(DSS)诱导UC大鼠模型,并给予药物处理。观察大鼠体重变化和粪便稠度等情况,评估疾病活动性指数(DAI);检测血清中促炎因子白细胞介素1β(IL-1β)水平;HE染色观察肠组织病理学变化;透射电子显微镜观察肠上皮细胞;RT-qPCR技术检测肠组织中miR-22水平;Western blot法检测肠组织中紧密连接相关蛋白ZO-1、occludin和claudin-1表达水平;双萤光素酶报告基因实验检测miR-22与NLRP3靶向关系。结果:对照组大鼠肠组织结构正常;模型组大鼠肠组织黏膜结构破坏严重,有大量炎症细胞浸润,屏障受损,细胞间隙增宽;低、高剂量柚皮素组大鼠肠组织损伤减轻;柚皮素+miR-22 antagomiR组大鼠肠组织损伤较高剂量柚皮素组明显加重,炎症细胞浸润增加。与对照组相比,模型组大鼠DAI、肠黏膜损伤肉眼评分、IL-1β水平及NLRP3蛋白表达水平显著升高(P0.05),miR-22水平及ZO-1、occludin和claudin-1蛋白表达水平显著降低(P0.05);与模型组相比,低、高剂量柚皮素组大鼠DAI、肠黏膜损伤肉眼评分、IL-1β水平及NLRP3蛋白表达水平显著降低(P0.05),miR-22水平及ZO-1、occludin和claudin-1蛋白表达水平显著升高(P0.05);与高剂量柚皮素组相比,柚皮素+miR-22 antagomiR组大鼠DAI、肠黏膜损伤肉眼评分、IL-1β水平及NLRP3蛋白表达水平显著升高(P0.05),miR-22水平及ZO-1、occludin和claudin-1蛋白表达水平显著降低(P0.05)。结论:柚皮素通过上调miR-22水平,抑制NLRP3炎症小体活化,发挥对UC大鼠肠屏障的保护作用。     

CCR5第一、二胞外环特异性结合的拮抗短肽对TNBS诱导SD大鼠结肠炎的治疗作用

目的:研究C-C趋化因子受体5(CCR5)膜外第一、二胞外环(ECL1和ECL2)特异性结合的拮抗短肽对三硝基苯磺酸(TNBS)诱导的结肠炎模型大鼠的治疗作用与机制。方法:采用100 mg/kg TNBS诱导结肠炎SD大鼠模型;用不同剂量的2条拮抗短肽(ECL1:25、35和45 mg/kg;ECL2:15、25和35 mg/kg)分别作用于模型大鼠,观察其对大鼠疾病活动指数(DAI)、结肠大体损伤指数(CMDI)和组织病理学改变的影响,采用real-time PCR和Western blot法分别检测结肠组织TNF-α和COX-2的mRNA与蛋白表达水平。结果:与模型组相比,有效剂量的ECL2拮抗短肽HY治疗组大鼠疾病活动程度、肠道溃疡及病理组织学损伤均有明显减轻,各评分指数差异具有统计学意义(P0.05);TNF-α和COX-2的蛋白和mRNA表达水平均明显下降(P0.05)。ECL1拮抗短肽GH作用的大鼠结肠炎症状评分及TNF-α和COX-2炎症因子表达无明显改变。结论:ECL2拮抗短肽可能通过下调结肠黏膜TNF-α和COX-2的表达来缓解TNBS诱导的SD大鼠结肠炎,而ECL1拮抗短肽的作用不明显。     

基于IL-33 / ST2 信号通路的茯苓多糖调控溃疡性结肠炎大鼠肥大细胞活化的机制研究

目的:探究基于IL-33/ST2信号通路的茯苓多糖调控溃疡性结肠炎(UC)大鼠肥大细胞(MC)活化的机制。方法:SPF级SD大鼠90只,15只大鼠为对照组,其余大鼠采用三硝基苯磺酸(TNBS)灌肠法建立UC模型,造模成功后大鼠分为模型组、茯苓多糖低剂量组(5 mg/kg)、中剂量组(100 mg/kg)、高剂量组(200 mg/kg)、柳氮磺胺吡啶组(SASP组)(300 g/kg),各组15只进行灌胃治疗,对照组、模型组每天灌胃生理盐水10 ml/kg,连续治疗14 d;治疗前后称量大鼠体质量,对大鼠进行疾病活动指数(DAI)评分,组织学损伤(TDI)评分,结肠黏膜损伤指数(CMDI)评分,HE染色观察病变部位炎症程度,甲苯胺蓝法检测MC形态、数目、脱颗粒率,免疫组化检测胰蛋白酶(TA)表达水平,ELISA法检测血清IL-33、IL-5、IL-13、IL-6、sST2的水平;Western blot检测结肠组织IL-33、ST2蛋白表达情况。结果:与对照组比较,模型组大鼠皮毛干枯、饮食量减少,黏膜腺体结构排列紊乱,炎症细胞浸润,MC数目、TA水平及IL-33、IL-5、IL-13、IL-6、sST2的水平升高(P0.05);与模型组比较,茯苓多糖组和SASP组大鼠饮食量增加,精神状态改善,黏膜损伤及炎症细胞减轻,MC数目、TA水平、IL-33、IL-5、IL-13、IL-6、sST2的水平显著降低,尤以茯苓多糖高剂量组和SASP组治疗效果最为显著(P0.05)。结论:MC活化在UC发病机制中发挥重要作用,中药茯苓多糖和SASP对UC均具有明显的治疗作用,茯苓多糖可通过抑制IL-33/ST2信号通路的激活,减少MC活化,抑制炎症因子的表达,降低结肠炎症浸润程度。     

金丝桃苷对溃疡性结肠炎大鼠的保护作用及机制研究

目的 观察金丝桃苷(Hyp)对三硝基苯磺酸(TNBS)诱导的大鼠溃疡性结肠炎(UC)的治疗作用,并初步探讨其作用机制.方法 直肠给予Wistar大鼠TNBS/乙醇溶液以复制大鼠UC模型,灌胃给予低、中、高剂量的Hyp(25、50、100 mg/kg)对其进行治疗,于给药7d后处死大鼠,观察结肠大体、组织病理学及湿质量指...     

绿茶多酚抑制肠道JAK2/STAT3信号通路保护三硝基苯磺酸诱导的小鼠结肠炎肠黏膜屏障

目的探讨绿茶多酚(GTP)对2,4,6-三硝基苯磺酸(TNBS)诱导的结肠炎小鼠的治疗作用及可能机制。方法建立TNBS结肠炎模型,将造模成功的小鼠随机分为模型组和GTP处理组,每组10只。GTP处理组小鼠每日给予0.2 mL GTP灌胃(100 mg/kg),模型组每日给予0.2 mL生理盐水灌胃。处理4周后处死小鼠,采用HE染色评估疾病活动度,采用ELISA检测小鼠结肠黏膜组织匀浆白细胞介素10(IL-10)、IL-6、肿瘤坏死因子α(TNF-α),免疫荧光染色检测肠黏膜屏障紧密连接蛋白1(ZO-1)及密封蛋白1(claudin-1)的表达,Western blot法检测肠黏膜ZO-1、claudin-1、磷酸化的Janus激酶2(p-JAK2)、磷酸化的信号转导子与转录激活子3(p-STAT3)的蛋白水平。结果在GTP处理的第3周及第4周,小鼠疾病活动指数均显著低于模型组小鼠。GTP处理组小鼠的结肠炎症评分及肠黏膜IL-6、TNF-α水平显著低于TNBS组,而IL-10显著高于TNBS组。与TNBS组小鼠相比,GTP处理显著提高小鼠claudin-1、ZO-1的表达水平,且小鼠肠黏膜p-JAK2及p-STAT3表达水平显著降低。结论GTP通过抑制肠道JAK2/STAT3信号通路发挥抗炎及肠黏膜屏障结构保护作用。     

Neutrophil Transmigration in Inflammatory Bowel Disease Is Associated with Differential Expression of Epithelial Intercellular Junction Proteins

Inflammatory bowel disease (IBD) consisting of ulcerative colitis (UC) and Crohn's (CD) typically displays a waxing and waning course punctuated by disease flares that are characterized by transepithelial migration of neutrophils (PMN) and altered barrier function. Since epithelial barrier function is primarily regulated by the apical most intercellular junction referred to as the tight junction (TJ), our aim was to examine expression of TJ and adherens junction (AJ) proteins in relation to PMN infiltration in mucosal tissue samples from patients with active IBD. Expression of epithelial intercellular TJ proteins (occludin, ZO-1, claudin-1, and JAM) and subjacent AJ (beta-catenin and E-cadherin) proteins were examined by immunoflourescence/confocal microscopy, immunohistochemistry, and Western blotting. Colonic mucosa from patients with UC revealed dramatic, global down-regulation of the key TJ transmembrane protein occludin in regions of actively transmigrating PMN and in quiescent areas in the biopsy samples. Significant decreases in occludin expression were observed at the protein and mRNA levels by Western and Northern blotting. In contrast, expression of other TJ and AJ proteins such as ZO-1, claudin-1, JAM, beta-catenin, and E-cadherin were down-regulated only in epithelial cells immediately adjacent to transmigrating PMN. Analysis of inflamed mucosa from Crohn's disease patients mirrored the results obtained with UC patients. No change in TJ and AJ protein expression was observed in colonic epithelium from patients with collagenous colitis or lymphocytic colitis that are respectively characterized by a thickened subepithelial collagen plate and increased intraepithelial lymphocytes. These results suggest that occludin expression is diminished in IBD by mechanisms distinct from those regulating expression of other intercellular junction proteins. We speculate that down-regulation of epithelial occludin may play a role in enhanced paracellular permeability and PMN transmigration that is observed in active inflammatory bowel disease.     

The free radical scavenger edaravone suppresses experimental dextran sulfate sodium-induced colitis in rats

Recent studies suggest that the enhanced release of reactive oxygen species (ROS) plays an important role in the pathogenesis of clinical inflammatory bowel diseases (IBD) such as ulcerative colitis and Crohn's disease. In the present study, we investigated the effects of the free radical scavenger edaravone, which is used clinically as an anti-stroke agent, in the development of experimental dextran sulfate sodium (DSS)-induced colitis in rats. The rats were fed 4% (w/w of diet) DSS in standard powder chow for 8 days. The edaravone and vehicle saline were injected subcutaneously twice a day. After the experimental period, the wet colonic weight, macroscopic mucosal damaged area, histological damage score, mucosal myeloperoxidase (MPO) activity, mucosal tissue lipid peroxidate and serum interleukin-6 (IL-6) levels were measured. In the DSS-induced colitis model, edaravone treatment (1-20 mg/kg day) significantly reduced the wet colonic weight, macroscopic damaged area, and the histological damage score. Edaravone treatment also reduced mucosal MPO activity, mucosal tissue lipid peroxidate level and serum IL-6 level. In particular, edaravone at a dose of 20 mg/kg day significantly reduced mucosal MPO activity and serum IL-6 level. These results strongly support the involvement of ROS in the pathogenesis of DSS-induced colitis. A clinical effect for edaravone against IBD patients is strongly expected.     

Pathophysiological role of nitric oxide in rat experimental colitis

Overproduction of nitric oxide (NO) by inducible nitric oxide synthase (iNOS) may contribute to the pathophysiology of ulcerative colitis. A 2,4,6-trinitrobenzenesulfonic acid sodium salt (TNBS) colitis model was established to examine the effect of selective iNOS inhibition, by S-(2-aminoethyl) isothiouronium bromide (ITU), on colonic mucosal cell damage and inflammation. Rats, killed 7 days after TNBS, had increased colonic mucosal levels of iNOS and interleukin-8 (IL-8), in addition to severe colonic inflammation which was characterized by significantly increased colon weight, damage score and colonic myeloperoxidase activity (MPO) (a marker of neutrophil influx). TNBS-treated rats had markedly decreased body weight and thymus weight. Administration of colitic rats with ITU significantly inhibited iNOS activity/expression and tended to reduce mucosal levels of IL-8, but no effect on MPO activity was observed. Following ITU therapy, colitic rats had reduced colonic damage and losses in body weight and thymus weight were reversed. Improvement of TNBS colitis by ITU suggested that excess NO, produced by iNOS, may have contributed to the initiation/ amplification of colonic disease, by mechanisms including enhancement of IL-8 releaseNO-mediated enhancement of pro-inflammatory cytokine release was further investigated in vitro. Lipopolysaccharide (LPS) and interferon-γ (IFN-γ) stimulated release of nitrite, lactate dehydrogenase (LDH), TNFα, IL-1β and IL-8 from rat peritoneal macrophages, all of which were significantly reduced by ITU. This suggests that NO-mediated cell damage enhances pro-inflammatory mediator release from macrophages. In addition, enhancement of IL-8 and TNFα release was also partially NO-dependent in activated peritoneal neutrophils. Therefore, the amelioration of TNBS colitis by ITU could include inhibition of NO-mediated pro-inflammatory cytokine release.     

Protective effect of salvianolic acid B on NASH rat liver through restoring intestinal mucosal barrier function

Aim: To investigate the effect of Salvianolic acid B (Sal B) on the disease progress of NASH and change of intestinal barrier function. Methods: Sixty Sprague-Dawley (SD) rats were randomly divided into control group, model group and treated group, with the former given normal diet and the latter 2 groups rats fed high-fat diet. In treated group, rats were infused through the stomach with 1 mg/ml Sal B every day at a dose of 20 mL/kg body weight. All animals were killed at the 24th week and plasma levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TG), total cholesterol (TC), endotoxin (ET) and diamine oxdase (DAO) were analyzed using the blood samples. The histopathology of liver was observed by H&E staining. The expression changes of tight junction protein occludin and ZO-1 were analyzed by immunocytochemistry. Ultrastructural morphology of small intestinal tissues was investigated by transmission electron microscopy. Results: Plasma levels of ALT, AST, TG, TC, ET and DAO were significantly higher in model group than those in both control group and group treated with Sal B. In model group, vacuolated swelling of the cytoplasm with aggregates of chronic inflammatory cells was observed in the liver tissue but not in Sal B-treated group. NAFLD Activity Score in the treated group was significantly lower than that in model group. Immunohistochemical staining showed that Sal B administration recovered the expression of occludin and ZO-1, which was downregulated in the model group. Transmission electron microscopy analysis demonstrated that cell surface microvilli and major intercellular junctional complex including tight junction, gap junction and adherens junction were restored in Sal B-treated group. Conclusion: Sal B exerted protective function against high-fat diet-induced liver damage by restoring healthy barrier function of intestine in NASH rat model.     

The effect of a selective 5-lipoxygenase inhibitor,zileuton, on tissue damage in acute colonic inflammation in rats

Though the mechanism of tissue damage induced by colonic inflammation in ulcerative colitis is unknown, it has been established that the inflammatory mediator and potent neutrophil (PMN) chemotaxin, leukotriene B4(LTB₄), is present in elevated amounts in the inflamed mucosa. The unique role of 5-lipoxygenase in the production of leukotrienes has made it a target for inhibition. This study used a rat model of acute colonic inflammation induced by a single IP injection of Mitomycin-C to test the efficacy of a specific and potent 5-lipoxygenase inhibitor zileuton in the treatment of colonic inflammation. We hypothesized that after inducing colitis in rats with mitomycin-C, the administration of oral zileuton would inhibit leukotriene production, thus preventing PMN infiltration and subsequent tissue damage. Zileuton decreased colonic tissue damage as measured by Histological score. However, zileuton did not significantly decrease neutrophil infiltration measured by mucosal PMN or myeloperoxidase (MPO) levels. Although zileuton was successful in significantly decreasing the frequency of severe colitis in our model, the fact that the decrease in PMN count and MPO level was not statistically significant suggests that another mechanism may be involved in its anti-inflammatory effect.     

布拉氏酵母菌对DSS诱导的实验性结肠炎小鼠肠黏膜的屏障作用

目的观察布拉氏酵母菌对葡聚糖硫酸钠(dextran sulfacte sodium,DSS)诱导的实验性结肠炎小鼠肠黏膜屏障的影响。方法将50只BALB/c小鼠随机分成5组,分别为:正常对照组(A)、模型组(B)、美沙拉嗪组(C)、布拉氏酵母菌组(D)、联合治疗组(E)。采用2.5%DSS溶液诱导小鼠实验性结肠炎动物模型,将C、D、E组小鼠分别给予美沙拉嗪、布拉氏酵母菌、美沙拉嗪加布拉氏酵母菌联合灌胃治疗,计算小鼠疾病活动指数(disease activity index,DAI)评分,评估结肠黏膜组织损伤程度,并用Western blot法检测结肠黏膜紧密连接蛋白ZO-1、Occludin表达水平。结果模型组小鼠的DAI评分及结肠黏膜组织损伤程度明显高于正常组(p0.05),ZO-1及Ocluddin表达水平明显低于正常组(p0.05)。与模型组相比,美沙拉嗪组、布拉氏酵母菌组、联合治疗组的DAI评分及结肠黏膜组织损伤程度均明显减低(p0.05),ZO-1及Ocluddin表达水平明显增多(p0.05),联合治疗组效果更好。结论布拉氏酵母菌可对DSS诱导的结肠炎肠黏膜屏障功能起到保护作用,与美沙拉嗪联合应用效果更佳。     

Role of neutrophils in acetic acid-induced colitis in rats

Intrarectal administration of 4% acetic acid produces diffuse inflammation that ultimately results in erosions and ulcerations of the rat colon. Although this model of colitis has been used extensively over the past several years, there are no quantitative data available regarding the relationship between neutrophil infiltration and mucosal injury during times of active inflammation. Therefore, the objective of this study was to define the role of extravasated neutrophils as mediators of mucosal injury and inflammation in acetic acid-induced colitis. We found the intrarectal administration of 4% acetic acid produced an 11-fold increase in colonic mucosal permeability, a 9-fold increase in colonic MPO activity, and a 1.6-fold increase in colon weight at 48 h following administration of acetic acid. In addition, we found significant correlations between colonic MPO activity and mucosal permeability and between colonic MPO activity and colon weight (P < 0.01 for both). These data suggested that inflammatory neutrophils may mediate mucosal injury and inflammation in this model of colitis. To assess the role of circulating neutrophils, rats were rendered neutropenic for 48 h by the intraperitoneal administration of antiserum directed toward rat neutrophils (ANS). Although ANS treatment reduced both the number of circulating neutrophils and colonic MPO activity to less than 10% of control values, it did not attenuate the increases in colonic mucosal permeability nor did it attenuate the increases in colon weight produced by acetic acid. Histological inspection confirmed that ANS treatment was not effective in attenuating the injury to the epithelial barrier. These data demonstrate that infiltrating neutrophils do not mediate the mucosal injury and inflammation observed in acetic acid-induced colitis.This work was supported by grants from the NIH (DK39168), Crohn's and Colitis Foundation of America and Pharmacia LEO Therapeutics (Uppsala, Sweden).     

苦参碱对溃疡性结肠炎大鼠肠黏膜细胞因子和自由基的影响

目的探究苦参碱对溃疡性结肠炎大鼠肠黏膜细胞因子和自由基的影响及其机制。方法采用2,4,6-三硝基苯磺酸（TNBS）制造大鼠溃疡性结肠炎模型,运用苦参碱对大鼠溃疡性结肠炎进行治疗,以柳氮磺胺吡啶作为阳性对照。治疗结束后,剖取结肠,检测黏膜细胞中IL-1α、TNF-α、IL-6和IL-8等细胞因子的水平;检测结肠黏膜细胞中超氧化物歧化酶（SOD）、丙二醛（MDA）水平。另取部分结肠做组织显微镜检查,并对组织损伤评分进行数理统计。结果与模型组相比,苦参碱和柳氮磺胺吡啶均能极显著降低IL-1β、TNF-α、IL-6和IL-8水平（均P〈0．01）;与模型组相比,苦参碱和柳氮磺胺吡啶均能极显著升高结肠黏膜细胞SOD水平（P〈0．01）,极显著降低MDA水平（P〈0．01）;苦参碱和柳氮磺胺吡啶均能促进溃疡面愈合,减少病灶部位炎性细胞浸润,水肿及纤维化。结论苦参碱能明显抵抗溃疡性结肠炎炎性反应,增强机体免疫,通过调节肠黏膜细胞因子失衡和抑制黏膜细胞氧自由基的产生和抗氧化功能干预溃疡性结肠炎发病过程。     

Development of dextran sulphate sodium-induced experimental colitis is suppressed in genetically mast cell-deficient Ws/Ws rats

Ws/Ws rats have a small deletion of the c-kit gene, and are deficient in both mucosal-type mast cells (MMC) and connective tissue-type mast cells (CTMC). In the present study we investigated the role of intestinal MMC in the development of dextran sulphate sodium (DSS)-induced experimental colitis using Ws/Ws rats. Ws/Ws and control (+/+) rats were given a 3% DSS aqueous solution orally for 10 days, and the subsequent mucosal damage was evaluated macroscopically and histologically. The mucosal myeloperoxidase (MPO) activities and histamine levels were also measured. (i) DSS induced severe oedema and hyperaemia with sporadic erosions in the control (+/+) rats, but these changes were significantly attenuated in the Ws/Ws rats (P < 0.01). (ii) The microscopic mucosal damage score was lower in the Ws/Ws rats than in the control (+/+) rats (P = 0.06). (iii) There were no significant differences in mucosal MPO activity between the Ws/Ws and control (+/+) rats (P = 0.46). (iv) The mucosal histamine levels in the colon were significantly reduced in the Ws/Ws rats compared with the control (+/+) rats (P < 0.05). (v) Significant positive correlations were observed between mucosal histamine levels and the degree of mucosal oedema (calculated as colonic wet weight/protein content) (r = 0.778, P < 0.01), and between histamine levels and the macroscopic damage (r = 0.623, P < 0.05), respectively. (vi) DSS induced a local recruitment of MMC in the colonic mucosa of Ws/Ws rats, and mucosal damage gradually increased in accordance with this MMC recruitment. These results indicate that MMC play an important role in the development of DSS colitis.     

Suppressive effect of non-anaphylactogenic anti-IgE antibody on the development of dextran sulfate sodium-induced colitis

Inflammatory bowel disease (IBD) is a spectrum of immune-mediated chronic disorders of the intestine. Patients with IBD tend to exhibit significantly elevated levels of IgE in their serum. In general, the pathogenesis of IBD exhibits inflammatory events such as immunoglobulin E (IgE)-mediated hypersensitivity. We examined the effect of the non-anaphylactogenic anti-IgE antibody, which has been known to block IgE functions, in an animal model of ulcerative colitis induced by the oral intake of dextran sulfate sodium (DSS) for seven days. The non-anaphylactogenic anti-IgE antibody was subcutaneously injected on day 0 of DSS treatment. The disease activity index (DAI) was calculated by scoring intestinal states, including body weight loss, diarrhea, and rectal bleeding, and the activities of myeloperoxidase (MPO) and chymase were measured in the colon tissue. In addition, the expression of tumor necrosis factor (TNF)-alpha and cyclooxygenase (COX)-2 was determined by Western blotting. Administration of the anti-IgE antibody markedly reduced the histological damage to the colon and the DAI increment exhibited by the DSS-induced colitis. The anti-IgE antibody also significantly suppressed the activities of MPO and chymase as well as the expression of TNF-alpha and COX-2 in the DSS-treated colon tissue. Furthermore, the elevation of IgE levels in serum was induced by DSS and reduced by anti-IgE antibody injection. Thus, these results indicate that the IgE response played an important role in the clinical signs and the expression of inflammatory mediators in a colitis model caused by DSS treatment, suggesting that the non-anaphylactogenic anti-IgE antibody may be a useful therapeutic agent for ulcerative colitis.