黄芪多糖对铜绿假单胞菌致大鼠肺部感染的作用分析

目的分析黄芪多糖(astragalus polysaccharide, APS)对铜绿假单胞菌所致大鼠肺部感染的保护作用。 方法经气管内注射铜绿假单胞菌制备肺部感染模型,将40只SD雄性大鼠随机分为对照组(Control)、模型组(Model)及APS治疗组(模型+100 mg/kg APS(Model+APS100)及模型+200 mg/kg APS(Model+APS200)组)。造模后24 h处死大鼠,测定肺组织湿干重比(W/D),分别计数及ELISA测定支气管肺泡灌洗液的总炎症细胞数及TNF-α、IL-1β水平,使用Western blot法检测肺组织中NF-κB p65及IκBα蛋白磷酸化水平。 结果与Control组相比,铜绿假单胞菌显著诱导肺组织W/D增加(P<0.05),增加炎症细胞数(P<0.05),使TNF-α、IL-1β表达(P<0.05),并可诱导NF-κB p65/ IκBα发生磷酸化(P<0.05),而给予APS治疗可明显逆转上述变化(P<0.05),且高剂量组作用明显强于低剂量组(P<0.05)。 结论APS可能通过抑制p65/ IκBα活性,减少TNF-α及IL-1β的产生,从而减轻铜绿假单胞菌引起的肺部感染。     

红景天苷对内毒素诱导的RAW264.7细胞损伤拮抗作用的研究

目的:观察不同浓度的红景天苷（SDS）对内毒素（LPS）引起的巨噬细胞RAW264.7损伤的拮抗作用,并初步探讨其作用机制。方法: 将小鼠巨噬细胞RAW264.7随机分为正常对照组（A组）、LPS组(B组)、SDS (5 μg/ml)对照组（C组）、SDS(5 μg/ml)+LPS组（D组）、SDS(10 μg/ml) 对照组（E组）、SDS(10 μg/ml)+LPS组(F组)、SDS(20 μg/ml) 对照组(G组)和SDS(20 μg/ml)+LPS组(H组)。选取对数生长期的细胞,相继用SDS（0~20 μg/ml）预处理1 h及1 μg/ml LPS刺激24 h后,收集细胞,用MTT比色法检测细胞的活力。6 h后收集细胞用Western blot检测细胞中NF-κB的含量,用ELISA法检测细胞上清中TNF-α、IL-6和IL-10的含量,同时用光密度法检测细胞上清中LDH的含量。结果: LPS可显著降低细胞的活力（P<0.05,P<0.01）,增加NF-κB的表达（P<0.01）,并显著增加细胞上清中TNF-α、IL-6、IL-10和LDH的含量（P<0.05,P<0.01）。而SDS则可以浓度依赖的方式对抗LPS所致细胞活力的减低、NF-κB含量的增加,使TNF-α、IL-6和LDH的含量明显减少,IL-10的含量明显增加;但不同浓度的SDS对正常细胞的上述指标没有影响。结论: SDS对LPS引起的细胞损伤具有对抗作用,其作用可能与其抑制炎症介质的释放有关。     

双歧杆菌分泌型粘附素对肠上皮细胞应激反应的影响

目的 观察双歧杆菌分泌型粘附素对肠上皮细胞应激反应后核因子(NF)-κB DNA结合活性、细胞胞质核因子抑制蛋白κB(IκB)、细胞胞核NF-κB p65的表达和肿瘤坏死因子(TNF)-α、白细胞介素(IL)-1β、IL-8等细胞因子表达的影响.方法 经培养的肠上皮Lovo细胞分为5组,分别经LPS( 100 ng/ml)、H2O2( 200 μmol/L)直接刺激3h以及经双歧杆菌分泌型粘附素(30 μg/ml)预孵30 min后再予LPS( 100 ng/ml)、H2O2刺激(200 μmol/L)刺激3h,正常对照组未作任何处理.采用凝胶电泳迁移率试验(EMSA)方法检测NF-κB DNA结合活性;Western印迹法分别检测细胞胞质IκB和细胞胞核NF-κBp65的表达;RT- PCR方法检测TNF-α、IL-1β、IL-8等细胞因子mRNA的表达情况.结果LPS和H2O2刺激后,细胞表现出较高的NF-κB DNA结合活性[分别为正常对照组的(6.20±0.35)倍和(4.16±0.52)倍]和细胞胞核NF-κB p65的表达[分别为(0.64±0.05)和(0.67±0.06)],而细胞胞质IxB的表达则较弱[分别为(0.28±0.10)和(0.39±0.12)];以双歧杆菌分泌型粘附素预孵后,前二者活性明显降低,而后者的表达明显增强;LPS和H2O2处理后,TNF-α、IL-1β、IL-8等细胞因子mRNA的表达水平均明显增高[LPS处理组分别为(0.92±0.10)、(0.38±0.03)、(1.44±0.25),H2O2处理组分别为(0.89±0.13)、(0.36±0.06)、(1.42±0.18)],而粘附素预孵后则可显著降低它们的表达水平.NF-κB DNA结合活性与TNF-α、IL-1β、IL-8三种细胞因子的mRNA表达水平均呈显著正相关.结论 双歧杆菌分泌型粘附素对LPS和H2O2诱导的肠上皮细胞NF-κB DNA结合活性有显著抑制作用,NF-κB的活化可能与TNF-α、IL-1β和IL-8等炎性细胞因子的表达调控有关.     

脂多糖诱导巨噬细胞中核受体协同抑制因子启动子甲基化对炎症因子的调控作用

目的探讨核受体协同抑制因子(NCOR)在脂多糖(LPS)诱导巨噬细胞炎症反应中的作用及其调控机制。方法 1μg/ml的LPS分别处理小鼠巨噬细胞RAW264.7 24 h和48 h,应用Western blot和Real time-PCR检测NCOR的表达水平以及肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)mRNA水平,荧光素酶报告基因检测核因子-κB(NF-κB)的启动子活性。LPS处理细胞48 h后,应用MSP检测NCOR启动子是否发生甲基化以及Western blot检测DNMT3b的表达变化。Real time-PCR检测5'-aza和LPS联合处理细胞后NCOR mRNA的表达水平;转染DNMT3b siRNA后,分别应用Western blot和Real time-PCR检测DNMT3b的表达水平,以及DNMT3b siRNA和LPS联合作用下NCOR、TNF-α、IL-6的表达水平和NF-κB的启动子活性。结果 LPS干预细胞24、48 h后,NCOR蛋白和mRNA表达显著下调(P0.05),而TNF-α、IL-6 mRNA表达水平、DNMT3b蛋白的表达水平以及NF-κB的启动子活性显著上升(P0.05)。MSP检测说明LPS可介导NCOR的启动子甲基化。用5'-aza和LPS联合处理细胞后NCOR mRNA水平较LPS组有显著上升(P0.05)。采用DNMT3b siRNA可显著下调DNMT3b蛋白和mRNA水平,并可部分逆转LPS介导的抑制NCOR表达的效应,抑制TNF-α、IL-6的表达水平和NF-κB的启动子活性(P0.05)。结论 NCOR启动子的甲基化是LPS介导巨噬细胞炎症反应发生、发展的关键步骤,其可作为治疗ALI/ARDS的潜在靶点。     

Anti-inflammatory effects of bifidobacteria by inhibition of LPS-induced NF-κB activation

AIM: Different strains of bifidobacteria were analysed for their effects on HT-29 intestinal epithelial cells (IECs)in in vitro models both of the non-inflamed and inflamed intestinal epithelium.METHODS: A reporter gene system in HT-29 cells was used to measure levels of NF-κB activation after challenge with bifidobacteria or after bacterial pre-treatment following LPS challenge. IL-8 protein and pro-inflammatory gene expression was investigated using normal HT-29 cells.RESULTS: None of the bifidobacteria tested induced activation of nuclear factor KB (NF-κB) indicating that bifidobacteria themselves do not induce inflammatory events in IECs. However, six out of eight bifidobacteria tested inhibited lipopolysaccharide- (LPS-) induced NFκB activation in a dose- and strain-dependent manner. In contrast, NF-κB activation in response to challenge with tumor necrosis factor-α (TNF-α) was affected by none of the tested bifidobacteria, indicating that the inhibitory effect of bifidobacteria is specific for LPS-induced infiammation in IECs. As shown with two of the six inhibitionpositive bifidobacteria, LPS-induced inhibition of NFκB activation was accompanied by a dose-dependent decrease of interleukin 8 (IL-8) secretion and by lower mRNA levels for IL-8, TNF-α, cyclooxygenase 2 (Cox-2),and intercellular adhesion molecule 1 (ICAM-1).CONCLUSION: Some strains of bifidobacteria are effective in inhibiting LPS-induced inflammation and thus might be appropriate candidates for probiotic intervention in chronic intestinal inflammation.     

DAPK1在急性肺损伤小鼠肺组织中的表达及其作用

目的探讨死亡相关蛋白激酶1(DAPK1)在急性肺损伤小鼠肺组织中的表达及在炎症失控中的作用。方法将30只雄性C57小鼠按随机数字表法分为5组:正常对照组、LPS诱导急性肺损伤3、6、12、24 h组。应用2 mg/kg DAPK1抑制剂TC-DAPK 6预处理小鼠后,再用10 mg/kg LPS诱导小鼠肺损伤。HE染色光镜观察小鼠肺组织病理改变;免疫组化检测肺组织中DAPK1的表达和分布;应用RT-PCR和Western blot检测肺组织DAPK1和NF-κB p65的表达;ELISA检测血清炎症因子TNF-α、IL-6水平变化;Kaplan-Meier生存分析对各组小鼠存活时间进行分析。结果 LPS致伤组肺组织可见明显病理损伤改变且随时间进展加重,而DAPK1蛋白在正常对照组小鼠肺组织仅少量表达,在急性肺损伤小鼠肺组织中表达随时间进展明显增加;与正常对照组相比,LPS组肺组织DAPK1 mRNA蛋白表达水平均明显增高(P0.05),血浆炎症因子TNF-α、IL-6均明显升高(P0.05)。抑制小鼠肺DAPK1表达可明显降低LPS诱导的肺组织中DAPK1和NF-κB p65蛋白水平、血清炎症因子TNF-α、IL-6的水平(P0.05)。此外,抑制DAPK1可延长LPS致急性肺损伤小鼠的生存期(P0.01)。结论 DAPK1通过调控NF-κB炎症通路参与了LPS诱导的小鼠急性肺损伤,其可作为潜在的治疗靶点。     

Virulence Factors from Pseudomonas aeruginosa Increase Lung Epithelial Permeability

Pseudomonas aeruginosa infection frequently complicates lung injury and can be fatal in immunocompromised or debilitated individuals. Previous studies from our laboratory indicate that elastase from P. aeruginosa increases epithelial permeability by disrupting tight junctions between epithelial cells. Because the inflammatory reaction of the host is a prominent feature of bacterial infection, we reasoned that additional virulence factors from this organism could extend and augment the initial pulmonary injury by prompting accumulation of neutrophils. To test this hypothesis, we compared responses of guinea pigs to aerosols of elastase (PE) and lipopolysaccharide (LPS) from P. aeruginosa. After each treatment, we measured epithelial permeability and accumulation of neutrophils, interleukin 8 (IL-8), and β-glucuronidase in epithelial lining fluid (ELF). We found that PE increased epithelial permeability, as measured by both the clearance of aerosolized radiolabeled albumin from the air spaces and the concentration of plasma albumin in epithelial lining fluid, but it was less effective than LPS at recruiting neutrophils into the lungs. In contrast, LPS had no significant effect on epithelium, but it increased the concentration of neutrophils, IL-8, and β-glucuronidase in ELF. Increased epithelial permeability induced by PE does not cause lung inflammation, but it may facilitate the LPS-induced influx of neutrophils. Accepted for publication: 20 July 2000     

Berberine improves airway inflammation and inhibits NF-κB signaling pathway in an ovalbumin-induced rat model of asthma

Objectives: Berberine has been reported for its various activities including anti-inflammatory effects and has been used in treating many diseases. However, its effects on airway inflammation in asthma have not been investigated. This study mainly aimed to detect its effects on the airway inflammation and the nuclear factor-κB (NF-κB) signaling pathway activity in a rat model of asthma. Methods: Asthma was induced by ovalbumin (OVA) sensitization and challenge. The asthmatic rats were respectively treated with vehicle PBS or berberine (100 mg/kg or 200 mg/kg) for 28 days. The control rats were treated with PBS. Inflammatory cells in bronchoalveolar lavage fluid (BALF) were counted and the lung inflammation was scored. Levels of NF-κB p65 (mRNA and protein), phosphorylated NF-κB p65 (p-NF-κB p65), inhibitory κB alpha (IκBα) (mRNA and protein) and phosphorylated IκBα (p-IκBα), as well as NF-κB p65 DNA-binding activity, were measured to assess the activity of NF-κB signaling pathway. Levels of the downstream inflammatory mediators of NF-κB signaling, IL-1β, IL-4, IL-5, IL-6, IL-13 and IL-17 in BALF, were measured. Besides, the serum levels of OVA-specific immunoglobulin (Ig)E were measured. Results: Results showed that OVA increased the number of inflammatory cells in BALF, elevated lung inflammation scores, enhanced the NF-κB signaling activity and promoted the production of IgE in rats. Berberine dose-dependently reversed the alterations induced by OVA in the asthmatic rats. Conclusions: The findings suggested a therapeutic potential of berberine on OVA- induced airway inflammation. The ameliorative effects on the OVA-induced airway inflammation might be associated with the inhibition of the NF-κB signaling pathway.     

脂多糖诱导肺泡上皮细胞炎性损伤及损伤机制

目的 探讨细菌脂多糖(LPS)诱导的肺泡上皮细胞(AEC)炎症反应及可能的反应机制.方法 将人肺腺癌细胞系A549细胞株分为2组:对照组和LPS干预组,分别培养并于0.5 h、2 h、6 h和12 h时留取标本进行相关细胞因子检测.酶联免疫吸附法(ELISA)检测细胞间黏附分子-1(ICAM-1),放射免疫法检测肿瘤坏死因子-α(TNF-α)和白细胞介素-8(IL-8)的水平.实时荧光定量PCR检测TLR-4 mRNA的表达;蛋白质免疫印迹(Western blot)法检测核转录因子-κB(NF-κB)抑制蛋白IκBα和NF-κB p65蛋白水平,观察NF-κB的活性变化.结果 与对照组比较,LPS使AECs分泌的ICAM-1,TNF-α和IL-8于2 h、6 h和12 h均升高,ICAM-1,TNF-α于2 h、IL-8于12 h达分泌高峰;作用2 h后TLR-4 mRNA表达明显升高并达到峰值(27.88±13.31),6 h后(19.82±15.58)仍高于对照组(1.00±0.00),组间比较差异有统计学意义(P＜0.05),12 h时(12.86±11.45)组间比较差异无统计学意义(P＞0.05);NF-κB活性于刺激后0.5 h、2 h、6 h和12 h均明显增加,表现为抑制蛋白IκBα迅速降解,NF-κB p65蛋白同步释出并转入细胞核内.结论 LPS能够激活肺泡上皮细胞使其释放大量炎性因子,这一过程可能是通过激活TLR-4并进而激活NF-κB而诱导了AECs的炎性损伤.

Abstract：

Objective Lipopolysaccharide(LPS)can activate alveolar epithelial cells(AECs)and induce inflammatory injury.Toll-like receptor-4(TLR-4)is integrally involved in LPS signaling and plays a requisite role in the activation of NF-κB.NF-κB is a key intercellular signaling event that mediates cell inflammatory responses.The aim of the study wss to investigate in an in vitro model the inflammatory responses of AECs induced by LPS and the underlying mechanisms.Methods The study was performed on A549 cells(Human lung adenocarcinoma cell line).A549 cells were divided into 2 groups:a control group and a LPS stimulation group.Pminflammatory cytokines ICAM-1,TNF-α and IL-8 were detected by ELISA or radioimmunological methods.The expression of TLR-4 mRNA was detected by real time PCR.The activation of NF-κB was detected by Western blot(proteins of I-κBα and NF-κB p65).Results Compared with the control group.the ICAM-1 and TNF-α levels of the LPS-stimulated group were significantly higher,peaked after 2 h,and then gradually decreased at 6 and 12 h.IL-8 was also significantly increased after 2 h, which continued up to 12 h.The expression of TLR-4 mRNA in the LPS group was significantly higher,peaked after 2 h and gradually decreased at 6 and 12 h.NF-κB was activated after 0.5,2,6 and 12 h,indicated by the significant degradation of IκB-α and the significant release of NF-κB P65 and its subsequent translocation into the nucleus approximately synchronized.Conclusion The results demonstrate that LPS induced inflammatory injury in AECs via activating TLR-4 and subsequently NF-κB.     

NF-κB表达与糖尿病大鼠肺损伤的关系

目的探讨糖尿病大鼠肺脏的NF-κB表达情况及NF-κB的表达增强对肺脏损伤的程度。方法 30只10周龄SD大鼠随机分为正常对照组(A组,雌雄各5只)、糖尿病模型组(B组,雌雄各10只),采用链脲菌素诱导建立12周糖尿病大鼠模型。模型建立12周后,全部大鼠采用20%的乌拉坦1.35 g/kg腹腔内注射麻醉处死,并取左肺下叶固定切片。光学显微镜下观察肺组织炎症程度,免疫组织化学方法检测肺组织NF-κB表达的阳性面积百分比。结果 (1)肺部炎症观察:大多数正常对照组大鼠肺组织内未见炎症细胞。糖尿病模型组可见片状炎症细胞聚集,局部肺泡结构消失;(2)NF-κB的表达:NF-κB主要表达于气管、肺泡的上皮细胞内。正常对照组肺组织阳性表达明显弱于糖尿病模型组。分别对正常对照组和糖尿病模型组大鼠肺脏支气管上皮细胞和肺泡壁上皮细胞的NF-κB的表达做秩和检验(P0.05)具有明显统计学差异。结论 2型糖尿病大鼠模型肺组织内时炎症的改变程度较正常对照组相比明显加重,NF-κB的表达增加可能是糖尿病时肺脏病变的一个重要的危险因素。     

Anti-inflammatory effect of a selective IκB kinase-beta inhibitor in rat lung in response to LPS and cigarette smoke

RationaleIκB kinase (IKK) activates NF-κB which plays a pivotal role in pro-inflammatory response in the lung. NF-κB has been shown to be activated in alveolar macrophages and peripheral lungs of smokers and patients with chronic obstructive pulmonary disease. We investigated the anti-inflammatory effect of a highly selective and novel IKKβ/IKK2 inhibitor, PHA-408 [8-(5-chloro-2-(4-methylpiperazin-1-yl)isonicotinamido)-1-(4-fluorophenyl)-4,5-dihydro-1H-benzo[γ]indazole-3-carboxamide], in lungs of rat in vivo.MethodsAdult Sprague-Dawley rats were administered orally with PHA-408 (15 and 45 mg/kg) daily for 3 days and exposed to LPS aerosol (once on day 3, 2 h post-last PHA-408 administration) or cigarette smoke (CS; 2 h after PHA-408 administration for 3 days). Animals were sacrificed at 1, 4 and 24 h after the last exposure, and lung inflammatory response and NF-κB activation were measured.ResultsOral administration of IKKβ/IKK2 inhibitor PHA-408 significantly inhibited LPS- and CS-mediated neutrophil influx in bronchoalveolar lavage (BAL) fluid of rats. The levels of pro-inflammatory mediators in BAL fluid (CINC-1) and lungs (IL-6, TNF-α, IL-1β and GM-CSF) were also reduced by PHA-408 administration in response to LPS or CS exposures. The reduced pro-inflammatory response in PHA-408-administered rats was associated with decreased nuclear translocation and DNA binding activity of NF-κB in response to LPS or CS.ConclusionThese results suggest that IKKβ/IKK2 inhibitor PHA-408 is a powerful anti-inflammatory agent against LPS- and CS-mediated lung inflammation.     

间充质干细胞对内毒素诱导急性肺损伤大鼠NF-κB的影响

目的探索NF-κB在内毒素诱导急性肺损伤的发病机理及间充质干细胞治疗机理中的作用。方法 90只SD大鼠随机分为5组:A组:正常对照组(n=18)尾静脉注射等量生理盐水;B组:内毒素组(LPS)(n=18):经尾静脉注射LPS 5 mg/kg;C组:高剂量干细胞组(BMSCH组)(n=18):经尾静脉注射LPS 5 mg/kg+BMSC 2×106/ml 0.5 ml;D组:低剂量干细胞组(BMSCL组)(n=18):LPS 5 mg/kg+BMSC 1×106/ml 0.5 ml;干细胞对照组(BMSC组)(n=18):骨髓间充质干细胞2×106/ml 0.5 ml。分别于造模后6、24、72 h,处死动物收取标本,每个时间点6只(LPS的24 h组因1只死亡固只处死5只)。取肺组织于生理盐水中迅速漂洗干净后,立即放入液氮中冷冻,后转入-70℃冰箱中保存备用,分别测定肺组织TNF-α、IL-1β及肺组织细胞核内的NF-κB表达。结果 TNF-ɑ、IL-1β及NF-κB不同组之间存在显著差异,各组同一时间点的比较:B组均较A组显著性升高,P<0.05;C、D组低于B组,差异有统计学意义;E组与A组差异无统计学意义。结论 NF-κB在尾静脉注射内毒素诱导急性肺损伤大鼠的肺组织中表达升高。注射内毒素后立即经尾静脉注射小鼠骨髓间充质干细胞显著降低急性肺损伤大鼠的肺组织中的NF-κB的活性。     

内毒素急性肺损伤 TLR4-LPS 信号传导对 NF-κB 活性的影响黄继义简

目的 本文旨通过检测肺组织TLR4、NF-κB表达及支气管肺泡灌洗液炎症因子含量,探讨TLR4/NF-Kb信号在ALI发病中的作用.方法 30只大鼠随机分为对照组、ALI组和干预组.静脉注射LPS构建肺损伤模型,实时定量PCR及western blot检测肺组织TLR4、NF-κB表达,ELISA法检测TNF-α、IL-1β浓度.结果 肺损伤评分：ALI组〉TLR4拮抗剂干预组〉对照组,肺泡灌洗液TNF-α、IL-1β浓度较对照组分别增加了7倍和3.5倍.ALI组肺组织中TLR4和NF-κB表达明显增加,TLR4拮抗剂能抑制二者表达.结论 TLR4/NF-κB信号通路在脂多糖大鼠急性肺损伤模型的发展过程中起重要作用,TLR-4受体过表达诱导NF-κB活化及其下游炎症因子释放,加重急性肺损伤.     

Protective effect of bicyclol on lipopolysaccharide-induced acute lung injury in mice

Bicyclol is synthesized based on schisandrin, which is one of the main active components of Chinese herb Fructus Schisandrae. The purpose of this study is to investigate whether bicyclol has a beneficial effect on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. Bicyclol was given to mice by gavage for three times. ALI was induced by vena caudalis injection of LPS. The last dose of bicyclol was administrated 1 h before LPS given. Mice in each group were sacrificed at different time point after LPS administration. As revealed by survival study, pretreatment with high doses of bicyclol reduced the mortality of mice from ALI. Bicyclol pretreatment significantly improved LPS-induced lung pathological changes, inhibited myeloperoxidase (MPO) activity, and reduced lung/body and lung wet/dry weight ratios. Bicyclol also inhibited the release of TNF-α, IL-1β and HMGB1, whereas simultaneously increased the expression of IL-10. Furthermore, the phosphorylation level of NF-κB p65 was markedly decreased by bicyclol. Taken together, our study showed that bicyclol improves survival rate and attenuates LPS-induced ALI. The protective mechanism may be due to the inhibition of NF-κB activation and regulation of cytokine secretion.     

Inflammation in cystic fibrosis airways: relationship to increased bacterial adherence.

It is unclear whether inflammation in the cystic fibrosis (CF) lung relates predominantly to bacterial infection, or occurs as a direct consequence of mutant cystic fibrosis transmembrane conductance regulator (CFTR) protein. Interleukin (IL)-8 secretion from CF and non-CF cell lines, and from CF and non-CF human primary nasal epithelial cells incubated with or without Pseudomonas aeruginosa, was measured. Activation of nuclear factor-kappaB (NF-kappaB) in unstimulated CF and non-CF nasal epithelial cells, cell lines and murine tissues was measured by gel-shift assays. No significant difference in basal IL-8 production or NF-kappaB activation was observed between CF and non-CF primary nasal cells. However, CF cells exhibited a significantly (p<0.01) increased IL-8 secretion following P. aeruginosa stimulation. Equalization of the increased P. aeruginosa adherence observed in CF cells, to non-CF levels, resulted in comparable IL-8 secretion. Further, IL-8 production did not differ with mutations which result in either correctly localized CFTR, or in partial/total mislocalization of this protein. Similar levels of NF-kappaB activation were observed in a number of organs of wildtype and CF mice. Finally, IL-8 secretion and NF-kappaB activity were not consistently increased in CF cell lines. Cos-7 cell transfection with plasmids expressing deltaF508 or G551D mutant CFTR protein resulted in increased activation of a p50-containing NF-kappaB complex, but IL-8 secretion was similar to wild-type cells. The authors conclude that the stimulus produced by Pseudomonas aeruginosa is the predominant inflammatory trigger in their models.     

PM2.5通过上调颗粒酶B促进IL-18表达加重肺部炎症

目的颗粒酶B促进组织炎症的作用日益引起重视,但其在PM_2.5导致的肺部炎症中是否发挥作用还不清楚,本文对在PM_2.5导致的肺部炎症中颗粒酶B的作用进行了研究。 方法第一步构建经气管滴注PM_2.5混悬液诱导大鼠肺部炎症的动物模型,实验分组为PBS组、PM_2.5(2 mg/kg)组、PM_2.5(6 mg/kg)组、PM_2.5(18 mg/kg)组。通过设置PM_2.5滴注剂量梯度,检测不同PM_2.5暴露剂量下大鼠肺组织颗粒酶B表达、病理和炎症评分,以探讨颗粒酶B表达水平与肺部炎症严重程度间有无相关性。第二步通过阻断颗粒酶B,探究在PM_2.5导致的肺部炎症中颗粒酶B是否发挥促进作用。第三步通过阻断IL-18,探究在PM_2.5导致的肺部炎症中颗粒酶B是否通过IL-18发挥作用。 结果随着PM_2.5滴注剂量升高,肺组织颗粒酶B表达增加,肺组织病理切片炎症细胞浸润和肺水肿程度加重,炎症评分增加,PM_2.5促进了肺组织颗粒酶B表达和肺部炎症;阻断颗粒酶B抑制了IL-18表达和NF-κB磷酸化,改善了PM_2.5导致的肺部炎症;阻断IL-18抑制了NF-κB磷酸化,改善了PM_2.5导致的肺部炎症。 结论PM_2.5通过上调颗粒酶B促进IL-18表达加重肺部炎症,其机制可能与激活NF-κB信号通路有关。     

The effects of aerosolized dextran in a mouse model of Pseudomonas aeruginosa pulmonary infection

Airway infections initiated by the interaction of bacterial adhesins with carbohydrate receptors can be potentially prevented by nontoxic carbohydrate inhibitors. Intranasal inoculation of neonatal mice with Pseudomonas aeruginosa PAO1 caused pneumonia in 55% of control mice but in only 13% of mice inoculated 2 h after dextran inhalation (P<.001) and in 28% inoculated 4 h after dextran inhalation (P=.02). PAO1 adherence to epithelial cells was inhibited by 50% in the presence of dextran. Dextran was well distributed throughout the airways and stimulated tumor necrosis factor-alpha production in murine lungs but not interleukin-8 production by human epithelial cell lines. Phagocytosis of PAO1 was not affected by dextran nor was killing by human neutrophils diminished. Administration of dextran by aerosol may prevent murine pneumonia by impeding bacterial access to epithelial receptors and by stimulation of the immune functions of the epithelium.