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。     

参苓白术散通过TLR4 / NF-κB 通路对溃疡性结肠炎小鼠的抑制作用研究

目的:从TLR4/NF-κB信号通路角度观察参苓白术散对DSS诱导的小鼠溃疡性结肠炎(UC)的作用及机制。方法:实验小鼠分为空白组、模型组、参苓白术散高、中、低剂量组和美沙拉嗪组。除空白组外,其余各组均自由饮用3%DSS溶液一周以建立UC模型。造模成功后各给药组予相应药物灌胃,空白组与模型组给予0.5 ml生理盐水灌胃。观察各组小鼠疾病活动指数(DAI)和结肠病理改变,酶联免疫吸附测定法(ELISA)检测小鼠血清TNF-α、MIF、IL-10、EGF水平,免疫组化法检测小鼠结肠组织内TLR4、NF-κB p65蛋白表达。结果:与空白组比较,模型组小鼠DAI评分升高,结肠单位重量增加、长度变短,结肠黏膜病理受损严重,血清TNF-α、MIF含量显著升高,IL-10、EGF含量明显下降;结肠组织中NF-κB与TLR4蛋白表达上调(P0.01)。与模型组相比,参苓白术散低、中、高剂量组和美沙拉嗪组小鼠血清TNF-α、MIF含量显著降低,IL-10、EGF含量明显上升;结肠组织中NF-κB、TLR4蛋白表达下调(P0.01)。结论:参苓白术散对DSS诱导的小鼠UC有治疗作用,其作用可能与其调节TLR4/NF-κB通路及相关炎症因子,从而减轻肠道炎症反应,缓解肠黏膜损伤有关。     

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...     

美沙拉嗪通过抑制经典炎性信号通路激活治疗噁唑酮诱导的小鼠结肠炎中炎症反应

目的：探究美沙拉嗪在噁唑酮诱导的小鼠溃疡性结肠炎模型中的治疗作用与机制。方法：60只小鼠随机分为对照组、模型组、低剂量给药组和高剂量给药组，所有小鼠按照相同方式先后进行2次致敏。致敏5 d后麻醉小鼠，对照组小鼠按0.15 ml/g体重灌肠50%乙醇水溶液，灌注后倒置小鼠30 s，其余各组小鼠按相等剂量灌肠1%噁唑酮乙醇（50%）溶液。给药组按体重不同分别给予不同剂量的美沙拉嗪灌胃，对照组和模型组给予相同体积的溶剂灌胃。结果：噁唑酮造模后小鼠体重明显下降，给药组较模型组体重有所恢复；模型组小鼠肠道结构损伤严重，给药后炎症和损伤程度有所缓解；模型组小鼠血清中Th2型细胞因子含量显著增多（P<0.05），美沙拉嗪能够缓解炎症因子的大量释放，同时模型小鼠结肠组织NF-κB信号通路关键蛋白p-p65、p-IκB蛋白的表达显著增加，同时p65、IκB蛋白的降低，给药后蛋白水平恢复。结论：美沙拉嗪能够有效地恢复噁唑酮引起的小鼠体重下降和结肠组织炎性细胞浸润，同时能够保护噁唑酮引起的结肠组织损伤，美沙拉嗪同时对于噁唑酮诱导的Th2型细胞因子释放具有显著的抑制作用，可以通过抑制NF-κB通路的激活，从而经经典炎症通路发挥抗炎作用。     

谷氨酰胺对DSS诱导的小鼠结肠炎的治疗作用及机制

目的:探讨谷氨酰胺(Gln)对DSS诱导的小鼠结肠炎的治疗作用及机制。方法:8周龄BALB/c小鼠随机分为3组:Control组:对照;Gln组:DSS诱导结肠炎(4%DSS,7 d)+Gln治疗(1.5 g/kg,4周);DSS组:DSS诱导结肠炎。4周后处死小鼠评估结肠炎症、疾病活动度、上皮细胞凋亡、肠黏膜炎症因子及NF-κb(p65)信号通路。结果:Gln显著降低了DSS模型小鼠的结肠炎症、疾病活动度及上皮细胞凋亡。Gln抑制了肠黏膜NF-κb(p65)信号通路。结论:Gln治疗可减轻肠道炎症,降低肠上皮细胞凋亡,这可能是通过抑制肠黏膜NF-κB(p65)信号通路。     

复方蛹虫草改善DSS联合高脂饮食诱导的溃疡性结肠炎的作用和机制

目的探究复方蛹虫草(CCM)对葡聚糖硫酸钠(DSS)联合高脂诱导的溃疡性结肠炎(UC)的改善作用及初步机制。方法C57BL/6J雄性小鼠随机分为正常对照组、模型组、巴柳氮钠组及CCM 90、180和540 mg·kg~(-1)·d~(-1)组。采用DSS联合高脂饮食建立UC小鼠模型。造模同时ig给药,每天1次,连续8周,每周称量各组小鼠体质量,联苯胺法检测粪便隐血水平,酶联免疫吸附测定法(ELISA)测定血清细胞炎性因子TNF-α、IL-1β。HE染色法比较各组结肠组织病理改变,蛋白质免疫印迹(Western blot)方法检测结肠组织中IκB-α、NF-κBp65、TNF-α的表达。结果与正常组相比,模型组粪便隐血分数在第1、3、5、6周显著增加(P0.05);小鼠结肠组织发生明显炎性细胞浸润(P0.05);血清炎性因子TNF-α、IL-1β含量显著增高(P0.01);结肠组织TNF-α、NF-κBp65表达显著增高(P0.01),IκB-α表达显著降低(P0.01)。与模型组相比,CCM组小鼠体质量均显著降低(P0.05,P0.01);CCM组小鼠粪便隐血显著减少(P0.05);CCM高剂量组小鼠血清TNF-α显著降低(P0.05),CCM中剂量组小鼠血清IL-1β显著降低(P0.05);CCM中剂量组小鼠结肠组织炎性细胞浸润显著减少(P0.05);CCM给药各组小鼠结肠组织TNF-α、NF-κBp65表达显著降低(P0.01),IκB-α表达显著增高(P0.01)。结论 CCM可以改善DSS联合高脂诱导的溃疡性结肠炎,其机制可能与其抑制NF-κB通路的激活有关。     

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。     

罗格列酮通过抑制肠系膜脂肪组织炎症改善三硝基苯磺酸(TNBS)诱导的小鼠结肠炎

目的探讨过氧化物酶体增殖物激活受体γ(PPARγ)激动剂罗格列酮(rosiglitazone)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。方法选取雄性BALB/c小鼠20只建立TNBS结肠炎模型,造模成功后随机分为罗格列酮处理组及模型组,每组10只。罗格列酮处理组给予罗格列酮灌胃(0. 2 m L,[20 mg/(kg·d)]),模型组给予生理盐水(0. 2 m L/d)灌胃。处理6周后,处死所有小鼠。采用炎症性肠病疾病活动度指数(DAI)及HE染色结合Spencer结肠炎组织学评分评估两组小鼠肠道炎症程度及组织学改变,ELISA检测肠黏膜白细胞介素1β(IL-1β)、肿瘤坏死因子α(TNF-α)、IL-10水平及肠系膜脂肪组织IL-6、单核细胞趋化蛋白1(MCP-1)水平;脂肪组织HE染色后200倍光镜下拍照依据比例尺计算脂肪细胞直径;免疫组织化学染色法检测小鼠肠系膜脂肪组织F4/80阳性巨噬细胞浸润数量、脂肪细胞成熟标志物外周蛋白(peripherin)、脂连蛋白(adiponectin)及瘦素(leptin)水平。Western blot法检测小鼠肠系膜脂肪组织核因子κB(NF-κB)和信号通路中的NF-κBp65、磷酸化的NF-κBp65(p-NF-κBp65)、磷酸化的NF-κB抑制蛋白(p-IκB)及磷酸化的IκB激酶(p-IKK)的蛋白水平。结果罗格列酮处理后第5及6周,小鼠DAI评分显著低于模型组。同时,处理组小鼠肠黏膜IL-1β及TNF-α水平显著低于模型组,而IL-10水平显著高于模型组。与模型组小鼠相比,罗格列酮处理组小鼠肠系膜脂肪细胞直径及脂肪细胞成熟标志物perilipin水平均显著高于模型组。同时,罗格列酮处理组小鼠肠系膜脂肪组织巨噬细胞浸润数量及炎症介质IL-6、MCP-1水平均显著低于模型组。罗格列酮治疗显著促进处理组小鼠肠系膜脂肪细胞adiponectin的表达,而抑制leptin的水平。罗格列酮处理组小鼠肠系膜脂肪组织NF-κBp65、p-NF-κBp65、p-IKK及p-IκB蛋白水平均显著低于模型组。结论罗格列酮可显著抑制TNBS模型小鼠肠道炎症,可能与抑制肠系膜脂肪组织NF-κBp65通路有关。     

共刺激分子及黏附分子在大鼠实验性结肠炎中的表达研究

目的：探讨共刺激分子及黏附分子在大鼠实验性结肠炎发病中的作用。方法：建立三硝基苯磺酸诱导的实验性结肠炎大鼠模型，并予以泼尼松或柳氮磺胺吡啶治疗，设立正常对照及未治疗组对照，进行组织学评分；流式细胞仪检测各组外周血、脾脏和结肠上皮内单个核细胞CD28、CTLA-4及CD11b的表达。结果：实验性结肠炎大鼠在外周血、脾脏和结肠表达CD11b、CD28及CTLA-4均较正常对照组升高，有统计学意义，而经泼尼松或柳氮磺胺吡啶治疗后在结肠的CD11b和CD28的表达有所回落，而CTLA-4升高更加明显，均有统计学意义。结论：黏附分子可能参与了大鼠实验性结肠炎的发生，CD28与CTLA-4表达失调可能是发病机制之一，泼尼松和柳氮磺胺吡啶的治疗机制可能与共刺激分子及黏附分子有关。     

E3泛素连接酶RNF138抑制溃疡性结肠炎的发生及进展

目的 研究E3泛素连接酶RNF138在溃疡性结肠炎(UC)中的作用。方法 利用GEO数据库分析活动期、缓解期以及经免疫抑制剂治疗后UC样本中RNF138的表达水平；利用RNF138基因敲除小鼠构建UC模型，对模型小鼠进行病理学观察及组织学分析；取小鼠结肠组织进行转录组测序，初步探究RNF138敲除促进UC进展的可能机制；利用免疫组化和Western blot检测小鼠结肠组织中RNF138和phospho-NF-κB p65(p-p65)的表达水平；通过qPCR实验检测核因子NF-кB通路靶基因的表达水平；利用免疫组化对临床样本中RNF138和p-p65的表达进行检测。结果 GEO数据库及临床样本分析显示，与缓解期相比，活动期UC组织中RNF138表达下调(P<0.05);敲除RNF138促进DSS诱导的UC发生及进展(P<0.05);敲除RNF138促进p-p65及其靶基因表达(P<0.05),提示NF-кB信号通路激活。结论 RNF138通过阻断NF-кB通路活化抑制UC发生及进展。     

Haptic selective attention by foot and by hand

Nonvisual perceptions of a wielded object's spatial properties are based on the quantities expressing the object's mass distribution, quantities that are invariant during the wielding. The mechanoreceptors underlying the kind of haptic perception involved in wielding – referred to as effortful, kinesthetic, or dynamic touch – are those embedded in the muscles, tendons, and ligaments. The present experiment's focus was the selectivity of this muscle-based form of haptic perception. For an occluded rod grasped by the hand at some intermediate position along its length, participants can attend to and report selectively the rod's full length, its partial lengths (fore or aft of the hand), and the position of the grip. The present experiment evaluated whether participants could similarly attend selectively when wielding by foot. For a given rod attached to and wielded by foot or attached to (i.e. grasped) and wielded by hand, participants reported (by magnitude production) the rod's whole length or fractional length leftward of the point of attachment. On measures of mean perceived length, accuracy, and reliability, the degree of differentiation of partial from full extent achieved by means of the foot matched that achieved by means of the hand. Despite their neural, anatomical, and experiential differences, the lower and upper limbs seem to abide by the same principles of selective muscle-based perception and seem to express this perceptual function with equal facility.     

Luminol-independent chemiluminescence by phagocytes is markedly enhanced by dexamethasone,not by other glucocorticosteroids

The effect of several glucocorticosteroids on the generation of reactive oxygen species (ROS) was examined. The ROS assessed were O ₂ ^– , H₂O₂, OH·, and chemiluminescence (CL) (determined in the presence or absence of luminol), generated by both opsonized zymosan-stimulated neutrophils or monocytes and by the xanthine-xanthine oxidase system. Except for luminol-independent CL, only high concentrations (10^–4 M) of steroids could decrease each ROS. In contrast, luminol-independent CL generation in the phagocyte system was increased in a dose-dependent manner by the addition of dexamethasone, but not by any other steroid. Further, in lymphocyte cultures stimulated with Con A for four days, luminol-independent CL generation was demonstrated and enhanced by the addition of dexamethasone, although CL generation was not detected in the absence of dexamethasone. These findings provide evidence that CL does not always represent light specific to ROS, and they suggest the possibility that dexamethasone induces emission of light at sites of inflammation.     

Intrastromal invasion by limbal epithelial cells is mediated by epithelial-mesenchymal transition activated by air exposure

Corneal epithelial stem cells are located in the basal layer of the limbus between the cornea and the conjunctiva. Regulation of these limbal epithelial progenitor cells by the stromal niche dictates corneal surface health. To further characterize this process, limbal explants were cultured at the air-fluid interface, termed air-lifting, to stimulate the niche. As compared to submerged cultures, air-lifting significantly promoted epithelial stratification, migration, proliferation, and intrastromal invasion by limbal epithelial cells. Epithelial intrastromal invasion was noted when the limbal, but not corneal, epithelium was recombined with the limbal stroma containing live, but not dead, cells. Invading limbal basal cells displayed up-regulated nuclear expression of p63 and Ki67, down-regulated E-cadherin and cornea-specific keratin 3, and switched expression of beta-catenin from intercellular junctions to the nucleus and cytoplasm, indicating the activation of the Wnt/beta-catenin pathway. Invaded cells isolated by collagenase from the stroma of air-lifted, but not submerged, explants showed vivid clonal growth on 3T3 fibroblast feeder layers and complete epithelial-mesenchymal transition by expressing nuclear p63 and cytoplasmic S100A4. These findings collectively suggest that epithelial-mesenchymal transition via the Wnt/beta-catenin pathway influences the fate of limbal epithelial cells, likely to be progenitor cells, between regeneration and fibrosis when the stromal niche is activated.     

Cohesion by topology: sister chromatids interlocked by DNA

Sister chromatid cohesion is coupled with chromosome replication and influences chromosome segregation and intra-S repair. Specialized proteins, the cohesins, together with other pathways contribute to tether sister chromatids. In this issue of Genes & Development, Wang and colleagues (pp. 2426-2433 demonstrate that TopoIV, a type II DNA topoisomerase, modulates cohesion in Escherichia coli, by removing interlocked DNA junctions between sister chromatids. They propose that DNA precatenanes, arising during replication fork progression, hold sister chromatids together.