沙尘暴PM25、PM10对大鼠肺泡巨噬细胞炎性因子分泌的影响

目的：探讨沙尘暴PM2.5、PM10对大鼠肺泡巨噬细胞分泌NO、白细胞介素8(IL-8)及肿瘤坏死因子-α(TNF-α)的影响。方法沙尘暴颗粒物样品采自北京市城区，实验细胞为原代培养的大鼠肺泡巨噬细胞。细胞毒性测定用四甲基偶氮唑盐微量酶反应比色(MTT)法，NO的测定用Griess重氮化反应法，细胞因子IL-8、TNF-α的测定采用放射免疫法。结果(1)沙尘暴PM2.5、PM10作用24h后对大鼠肺泡巨噬细胞产生一定的细胞毒性。随着染毒剂量的增加，巨噬细胞存活率逐渐减低，高剂量组约为对照的80％。(2)20～150μg／ml的沙尘暴PM2.5、pm10染毒24h后均能剂量依赖性地诱导巨噬细胞分泌炎性因子NO、IL-8及TNF-α。(3)沙尘暴PM2．5的细胞毒性比相同浓度的PM10大，而对巨噬细胞分泌炎性因子NO、TNF-α的作用却小于PM10，结论：沙尘暴PM2.5、PM10可刺激大鼠肺泡巨噬细胞分泌炎性因子NO、IL-8及TNF-α。     

难治性支原体肺炎患儿相关炎性因子特征分析

目的探讨难治性支原体肺炎患儿相关炎性因子的临床特征。方法选取2014年1月-2016年12月该院所收治的68例难治性支原体肺炎患儿作为难治性支原体肺炎组,另选取同期医院所收治的68例支原体肺炎患儿作为支原体肺炎组。并比较和分析难治性支原体肺炎与支原体肺炎患儿血清炎性因子TNF-α、IL-6、IL-8、IL-10水平的变化情况,肺部有纤维化组与肺部无纤维化患儿血清及胸腔积液炎性因子TNF-α、IL-6、IL-8、IL-10水平的变化情况。结果难治性支原体肺炎组患儿血清炎性因子TNF-α、IL-6、IL-8、IL-10明显高于普通支原体肺炎组(P0. 05)。肺部有纤维化组患儿血清炎性因子TNF-α、IL-6、IL-8、IL-10,明显高于肺部无纤维化患儿(P0. 05)。肺部有纤维化患儿胸腔积液炎性因子TNF-α、IL-6、IL-8、IL-10,明显高于肺部无纤维化患儿(P0. 05)。结论 TNF-α、IL-6、IL-8、IL-10参与了难治性支原体肺炎的发病,并且在肺部纤维化的形成过程中发挥作用,可作为临床诊断病情及预后判断的重要参考依据。     

大气颗粒物PM10和PM2.5对人肺成纤维细胞及其炎性因子分泌的影响

目的 探讨大气颗粒物PM10和PM2.5对人肺成纤维细胞及其分泌肿瘤坏死因子(TNF-a)、白细胞介素6(IL-6)和白细胞介素8(IL-8)的影响.方法 于冬季采暖期采集颗粒物样品PM10和PM2.5,实验细胞为传代培养的人肺成纤维细胞,用剂量分别为25、50、100、200μg/ml的PM10和PM2.5对人肺成纤维细胞染毒24 h.采用四甲基偶氮唑盐微量酶反应比色法测定细胞毒性;放射免疫法测定炎性因子TNF-a、IL-6和IL-8.结果 25、50、100、200μg/ml的PM10作用于人肺成纤维细胞24 h后产生一定的毒性作用,低剂量时刺激细胞增殖,高剂量时抑制细胞增殖,各浓度时细胞存活率分别为118.80%,120.47%,107.42%,95.97%.25、50、100、200μg,/ml的PM2.5作用24 h后亦对人肺成纤维细胞产生一定的毒性作用,亦表现为低剂量时刺激细胞增殖,高剂量时抑制细胞增殖,各浓度时细胞存活率分别为107.81%,101.48%,91.86%,81.35%.PM10和PM2.5能刺激人肺成纤维细胞分泌炎性因子TNF-a、IL-6和IL-8,尤其200μg,/ml浓度时与对照组相比,各炎性分子浓度差异有统计学意义(P<0.05).结论 大气颗粒物PM10和PM2.5对人肺成纤维细胞有一定毒性作用;PM10和PM2.5染毒24 h后能诱导人肺成纤维细胞分泌炎性因子TNF-a、IL-6、IL-8.     

不同分散度的沙漠尘对大鼠肺损伤及细胞炎性因子分泌的影响

目的探讨不同分散度的沙漠尘对大鼠肺损伤和巨噬细胞分泌肿瘤坏死因子(TNF-α)、白细胞介素8(IL-8)和一氧化氮(NO)的影响。方法沙漠尘样品采自内蒙古腾格里沙漠。120只Wistar雄性大鼠随机分为阴性对照组、粒径≤2.5μm沙漠尘组、≤10μm沙漠尘组和SiO2阳性对照组,每组30只。将浓度均为60 mg/ml的SiO2、粒径≤2.5和≤10μm沙漠尘混悬液,按100 mg/kg染毒剂量、1.67 ml/kg染毒体积,采用气管内灌注法染毒两次,间隔15 d,阴性对照组灌注生理盐水。每组分别在染尘后1、3、6个月处死10只,取肺组织进行病理学检查。对原代培养的大鼠肺泡巨噬细胞染毒24 h后,采用四甲基偶氮唑盐(MTT)比色法测定细胞毒性,用酶联免疫法检测TNF-α和IL-8,用Griess重氮化反应法检测NO。结果粒径≤2.5、≤10μm组大鼠染毒后1个月时肺泡间隔增厚、细胞浸润,3个月时肺组织部分区域出现纤维化,6个月时出现较明显的尘肺结节样病变,且粒径≤2.5μm组纤维化面积相对较大。粒径≤2.5、≤10μm的沙漠尘作用巨噬细胞24 h后,随着染毒剂量的增加,其细胞毒性逐渐增强,最高剂量组的细胞存活率分别为72.42%和81.76%;诱导细胞分泌TNF-α、IL-8和NO量明显增加,染毒剂量为100、200μg/ml时,各炎性因子分泌量高于阴性对照组,差异有统计学意义(P0.05或P0.01)。结论粒径≤2.5、≤10μm的沙漠尘均能诱导大鼠肺巨噬细胞分泌炎性因子TNF-α、IL-8和NO的量增加,可使染尘大鼠发生典型的尘肺结节性病变。     

室内PM10与气传真菌对大鼠肺巨噬细胞吞噬功能的影响

[目的] 以体外培养SD大鼠肺泡巨噬细胞(AM)为靶细胞,研究PM10与气传真菌单独和联合染毒对它的非特异性免疫功能的影响,并阐明剂量-反应关系.[方法]采集室内PM10、气传真菌,配制成染毒溶液.用不同浓度的PM10、气传真菌,以及PM10和气传真菌联合染毒液染毒大鼠肺泡巨噬细胞,分别测定培养液中肺泡细胞存活率、吞噬率和吞噬指数以及细胞因子TNF-α,观察PM10与气传真菌单独和联合染毒对肺巨噬细胞存活率及其吞噬功能的影响.[结果]PM10和真菌均能引起AM存活率降低,且有一定剂量-效应关系,剂量越高,存活率越低(P<0.05).联合染毒组存活率低于相应单独染毒组.2×2析因试验设计的方差分析结果显示,与对照组相比,联合染毒组存活率下降,且具有显著性意义(P<0.01).提示PM10和真菌对巨噬细胞存活率的影响存在联合作用.单独和联合染毒组的吞噬率、吞噬指数也均呈剂量依赖性下降.高剂量组的吞噬率、吞噬指数远远低于阴性对照组(P<0.05).2×2析因试验设计方差分析结果表明,联合染毒组的吞噬率、吞噬指数与对照组相比,差异均有显著性意义(P<0.01),提示PM10和真菌对AM吞噬功能具有一定联合效应.结果还表明,阴性对照组培养上清液中未检测到TNF-α.染毒组TNF-α活性则随剂量上升而上升(P<0.05).但PM10和真菌单独染毒时的最高剂量组TNF-α活性反而降低了,这提示在适当增高剂量时,可使细胞合成与分泌TNF-α增加,但过高剂量时,细胞受损以至功能受抑.2×2析因试验设计的方差分析结果显示,与对照组相比,联合染毒组TNF-α活性改变有显著性意义(P<0.05).联合染毒组TNF-α活性约等于相应单独染毒组的TNF-α活性之和.[结论]室内PM10和气传真菌有细胞毒性,并能损害肺泡巨噬细胞的吞噬功能,并且能增加肺泡巨噬细胞产生TNF-α.提示在作用终点上,PM10和气传真菌有相加作用.     

染料木黄酮对脂多糖诱导的RAW264.7细胞炎症因子、腺苷酸激活蛋白激酶磷酸化的影响

目的研究染料木黄酮(genistein,Gen)对脂多糖(LPS)诱导的巨噬细胞炎症因子产生和腺苷酸激活蛋白激酶(AMPK)磷酸化的影响。方法体外培养RAW 264.7小鼠单核巨噬细胞,加入1、5、10、50、100 mol/L的Gen共同培养,MTT法检测其对细胞活性的影响。将RAW264.7细胞随机分为4组:空白对照组不加任何药物,模型组加入终浓度为1 g/ml的LPS进行刺激,Gen高、低剂量组分别加入终浓度为10、5 mol/L的Gen预处理1h后,再加入终浓度为1 g/ml的LPS刺激,24h后收取细胞上清用酶联免疫(ELISA)方法检测TNF-α、IL-6含量,Westernblot检测AMPKα蛋白及其磷酸化的表达水平。结果 100 mol/L的Gen对体外培养RAW264.7细胞的增殖有影响,而其他浓度则无。LPS处理的RAW 264.7细胞与对照组比较,TNF-α、IL-6生成显著增多(P<0.01)、AMPKα磷酸化水平显著降低(P<0.01),而AMPKα总蛋白表达水平无差异(P>0.05)。Gen干预可减少LPS诱导的TNF-α、IL-6生成,上调AMPKα磷酸化水平的表达,与LPS组相比,差异均有统计学意义(P<0.01)。结论 Gen能抑制LPS诱导巨噬细胞的炎症反应,减少TNF-α、IL-6生成,这可能与Gen促进AMPKα磷酸化,从而激活AMPKα有关。     

苜草素对巨噬细胞吞噬活性和NO、IL-6、TNF-α分泌的影响

目的研究苜草素对小鼠巨噬细胞RAW264.7吞噬活性和NO、IL-6、TNF-α的影响,探讨苜草素对巨噬细胞免疫功能的影响机制。方法以不同浓度的苜草素和10 g/ml的脂多糖(LPS)分别处理巨噬细胞RAW264.7,采用中性红法测定巨噬细胞的吞噬活性,ELISA检测TNF-α分泌量。以不同浓度的苜草素处理LPS诱导的巨噬细胞RAW264.7,采用Griess分析法测定NO含量,ELISA检测IL-6分泌量,半定量RT-PCR方法测定巨噬细胞中iNOS、IL-6、TNF-αmRNA水平。结果苜草素在0.4、0.6、0.8和1.0 mg/ml时能显著提高巨噬细胞RAW264.7的吞噬活性(P<0.05);在0.6、0.8和1.0 mg/ml时显著增加TNF-α的分泌量(P<0.01),显著降低LPS诱导的巨噬细胞NO产生量(P<0.05);在0.2、0.4、0.6、0.8和1.0 mg/ml时显著降低LPS诱导的巨噬细胞IL-6的产生量(P<0.01)。苜草素可抑制LPS诱导的iNOS mRNA和IL-6 mRNA的表达,增加TNF-αmRNA的表达。结论苜草素可以提高巨噬细胞RAW264.7的吞噬活性,在转录水平上影响小鼠巨噬细胞iNOS、IL-6、TNF-α的基因表达,对巨噬细胞免疫功能起调节作用。     

纳米ZnO颗粒对小鼠肺泡巨噬细胞吞噬功能和炎症反应的影响

目的:研究纳米ZnO颗粒对小鼠肺泡巨噬细胞吞噬能力和炎性因子的影响。方法:采用不同尺寸的纳米ZnO颗粒对小鼠肺泡巨噬细胞进行染毒,通过中性红法测定小鼠肺泡巨噬细胞的吞噬能力,采用酶联免疫法测定炎性因子。结果:高浓度时(20μg/ml),小鼠肺泡巨噬细胞的吞噬能力明显降低;浓度为5～20μg/ml时,TNF-α、IL-6和IL-8均显著升高,并且10～30 nm ZnO颗粒处理组TNF-α和IL-6升高显著高于其他ZnO颗粒处理组。结论:纳米ZnO颗粒降低小鼠肺泡巨噬细胞的吞噬能力并引起炎性反应。     

竹荪醇提物对脂多糖诱导的RAW264.7细胞炎症反应的影响

目的探讨竹荪醇提物对LPS诱导的RAW264.7细胞肿瘤坏死因子(TNF-α)、一氧化氮(NO)的分泌,TNF-α、诱导型一氧化氮合酶(iNOS)、白细胞介素6(IL-6)、白细胞介素10(IL-10)的m RNA水平以及核转录因子(NF-κB)p65蛋白表达的影响及可能的抗炎机制。方法以不同浓度(100、200、400μg/ml)的竹荪醇提物作用于LPS(1μg/ml)诱导的RAW264.7小鼠巨噬细胞,采用ELISA法和Griess法检测炎性介质TNF-α和NO的分泌量;RT-PCR法测定促炎介质TNF-α、iNOS、IL-6和抗炎介质IL-10的m RNA水平;Western blot检测NF-κB p65蛋白的表达水平。结果与LPS组相比,200、400μg/ml的竹荪醇提物能显著抑制LPS诱导的RAW264.7细胞TNF-α和NO的释放(P0.01);且不同程度抑制RAW264.7细胞中促炎介质iNOS、TNF-α和IL-6的m RNA表达水平(P0.01),剂量依赖性的促进抗炎介质IL-10的m RNA表达水平(P0.01);不同浓度的竹荪醇提物均可显著抑制LPS诱导RAW264.7细胞中NF-κB p65蛋白的表达,差异有统计学意义(P0.01)。结论竹荪醇提物可抑制LPS诱导的RAW264.7细胞TNF-α和NO的释放,其抗炎作用的发挥可能与抑制NF-κB p65蛋白的表达,从而调节炎性介质的基因水平有关。     

气管滴注硫酸镍对大鼠炎症和肺损伤发生的影响

目的观察气管滴注硫酸镍对大鼠的急性毒性作用及其机制。方法将28只体重为280～310g的雄性Wistar大鼠随机分为对照组、硫酸镍低、中、高剂量组,根据镍在细颗粒物中的含量,设计镍的染毒剂量分别为7.5、75和750μg/kg。采用一次性气管滴注染毒,24h后处死动物,收集支气管肺泡灌洗液(BALF)进行细胞计数,总蛋白(TP)、乳酸脱氢酶(LDH)和炎性因子(IL-6、TNF-α)的测定;收集血液测定血清中炎性因子(IL-6、TNF-α)、C-反应蛋白(CRP)和镍的水平。结果不同剂量硫酸镍均可引起大鼠BALF中白细胞总数、中性粒细胞数、巨噬细胞显著升高(P<0.01),较高剂量Ni(75和750μg/kg)可引起BALF中TP水平、LDH活力和炎性因子IL-6、TNF-α水平显著增高(P<0.05或P<0.01);硫酸镍染毒24h后,大鼠血清TNF-α水平明显增高,与对照组相比差异有显著性(P<0.05);血清CRP水平随硫酸镍剂量升高而增高,但仅高剂量组差异有显著性(P<0.05)。此外,随着硫酸镍染毒剂量的增加,血清中镍水平也呈现明显的上升趋势。结论硫酸镍气管滴注可引起Wistar大鼠急性肺损伤和全身炎症反应,与含相同剂量镍的PM2.5相比,硫酸镍的作用较弱,提示镍在PM2.5的毒性作用中可能发挥重要作用,但PM2.5中其他成分的作用也不容忽视。     

Effects of submicrometer particle compositions on cytokine production and lipid peroxidation of human bronchial epithelial cells

To identify the size and components related to toxicity of ambient particles, we used a trichotomous impactor to collect 17 sets of particles in three size ranges--submicrometer (diameters < 1 microm; PM1.0, fine (diameters between 1 and 2.5 microm; PM1.0-2.5, and coarse (diameters between 2.5 and 10 microm; PM2.5-10--at stations monitoring background, urban, traffic, and industrial air in Taiwan. Elemental contents, carbon contents, soluble ions, and endotoxin content of particles were determined by X-ray fluorescence spectrometry, thermal analysis, ion chromatography, and the Limulus amebocyte lysate assay, respectively. Human bronchial epithelial BEAS-2B cells were exposed to particle extracts at 100 micro g/mL for 8 hr, and interleukin-8 (IL-8) concentrations in the medium and lipid peroxidation products were measured. Particle-induced tumor necrosis factor-alpha (TNF-alpha) production by mouse macrophage RAW 264.7 cells was also measured. PM1.0 stimulation resulted in significantly higher IL-8 production and lipid peroxidation than PM2.5-10, whereas the responses elicited by PM1.0-2.5 were not significantly higher than blank filters. Untreated and polymyxin B-pretreated PM1.0 also stimulated more TNF-alpha production by RAW 264.7 cells than PM2.5-10 and PM1.0-2.5. Cytokine production was significantly associated with metal contents of PM1.0: IL-8 correlated with Cr and Mn, and TNF-alpha correlated with Fe and Cr. Lipid peroxidation in BEAS-2B cells correlated with elemental and organic carbon contents. Our study found that size and composition of ambient particles were both important factors in inducing cytokine production and lipid peroxidation.     

浒苔多糖粗提物调节巨噬细胞RAW264.7免疫功能研究

目的通过浒苔多糖粗提物对RAW264.7巨噬细胞体外培养的干预研究,探索对该细胞免疫功能的影响。方法对RAW 264.7巨噬细胞进行培养,用四唑氮蓝（MTT）比色法测定巨噬细胞增殖;ELISA法测定细胞因子分泌量的变化。结果在一定浓度范围和干预时间内,浒苔多糖粗提物促进RAW264.7增殖,且随干预浓度增加,TNF-α和IL-6分泌显著增多。结论浒苔多糖粗提物对巨噬细胞RAW264.7具有免疫调节作用。     

Induction of IL-6 and inhibition of IL-8 secretion in the human airway cell line Calu-3 by urban particulate matter collected with a modified method of PM sampling

Exposure to particulate matter (PM) induces inflammatory cytokines. In the present study, we evaluated the secretion of IL-6 and IL-8 by an airway cell line exposed to PM with a mean aerodynamic size equal to or less than 10 or 2.5 μm (PM₁₀ and PM_2.5, respectively) collected in Mexico City, using a modified high-volume sampling method avoiding the use of solvents or introducing membrane components into the samples. PM was collected on cellulose-nitrate (CN) membranes modified for collection on high-volume samplers. Composition of the particles was evaluated by particle-induced X-ray emission (PIXE) and scanning electron microscopy. The particles (10-160 μg/cm²) were tested on Calu-3 cells. Control cultures were exposed to LPS (10 ng/mL to 100 μg/mL) or silica (10-160 μg/cm²). IL-6 and IL-8 secretions were evaluated by ELISA. An average of 10 mg of PM was recovered form each cellulose-nitrate filter. No evidence of contamination from the filter was found. Cells exposed to PM₁₀ presented an increase in the secretion of IL-6 (up to 400%), while IL-8 decreased (from 40% to levels below the detection limit). A similar but weaker effect was observed with PM_2.5. In conclusion, our modified sampling method provides a large amount of urban PM free of membrane contamination. The urban particles induce a decrease in IL-8 secretion that contrasts with the LPS and silica effects. These results suggest that the regulation of IL-8 expression is different for urban particles (complex mixture containing combustion-related particles, soil and biologic components) than for biogenic compounds or pure mineral particles.     

Differences in IL-10 and IL-12 production patterns and differences in the effects of acute ethanol treatment on macrophages in vivo and in vitro.

Several recent studies have documented that signaling can be fundamentally different in vivo and in vitro. However, studies of signaling and cytokine production by macrophages are often conducted in vitro, without confirmation in vivo. In addition, the direct effects of drugs and chemicals, including ethanol, on these processes are also often investigated in vitro. The purpose of the present study was to compare production of interleukin-6 (IL-6), IL-10, and IL-12 by macrophages in response to two different ligands for toll-like receptors and the effects of acute ethanol exposure on these responses in vivo and in vitro. The macrophage-like cell line RAW 264.7 is also widely used in cytokine and signaling studies, so these cells were also evaluated in this study. The results indicate that IL-6 production and the effects of Ethanol on IL-6 were similar in vivo and in vitro. In contrast, IL-10 was produced to a much greater extent in vitro than in vivo, and IL-12 was often undetectable in vitro even though it was produced at greater concentrations than IL-10 in vivo. To determine the role of altered secretion of preformed IL-10 as compared to new synthesis, cells were treated in vitro with protein and mRNA synthesis inhibitors. The results suggest that preformed IL-10 is released in vivo, but almost all IL-10 secreted in vitro is newly synthesized. Ethanol suppressed IL-12 and enhanced or had no effect on IL-10 production in vivo, whereas it decreased IL-10 production in vitro. These effects were similar at different times and using different concentrations of toll-like receptor ligands. In general, RAW 264.7 cells responded similarly to peritoneal macrophages in vitro. This suggests that results for cytokine studies and probably signaling studies as well that are conducted in vitro should be interpreted with caution and confirmed in vivo, particularly if they involve IL-10 and IL-12.     

大气混合污染物对大鼠肺组织CC16及细胞因子的影响

目的测定大气污染物对大鼠肺组织CC16、TNF-α和IL-6的mRNA表达影响。方法用日本产低流量PM10空气采样器采集PM10颗粒物,采样滤膜用生理盐水超声震荡洗脱,混悬液定容为15mg/ml。48只体重为200~240g Wistar大鼠随机分为3个实验组和1个对照组。实验组大鼠分别气管注入15mg/ml PM10的生理盐水混悬液1ml,对照组大鼠注入1ml生理盐水。次日,实验组大鼠静态吸入浓度分别为15、12、400mg/m3的SO2、NO2、CO空气混合气,每天吸入2h,对照组吸入正常空气。于吸入气体污染物1天、7天和30天后次日分别处死实验组和对照组大鼠,取肺组织,采用RT-PCR方法测定TNF-α、IL-6和CC16的mRNA表达水平;采用免疫组化和Western blotting测定肺和BALF中CC16的水平。结果吸入大气污染物组在吸入后1天和7天其肺组织CC16 mRNA的表达量明显低于对照组;细胞因子TNF-α和IL-6 mRNA表达增强,高于对照组,并于染毒初期即染毒第1天和第7天增高明显,染毒第30天,又呈下降趋势。免疫组化检测显示,实验组大鼠肺组织CC16表达水平在染毒后1天,7天时显著高于对照组,而在30天时低于对照组。BALF中CC16表现为1天和7天时显著低于对照和30天组。结论大气污染物作用于大鼠呼吸系统后,大鼠肺组织和BALFCC16表达量下降,TNF-α和IL-6 mRNA表达增强,并且在污染物作用早期变化明显。     

Proinflammatory and cytotoxic effects of Mexico City air pollution particulate matter in vitro are dependent on particle size and composition

Exposure to urban airborne particulate matter (PM) is associated with adverse health effects. We previously reported that the cytotoxic and proinflammatory effects of Mexico City PM10 (less than or equal to 10 micro m mean aerodynamic diameter) are determined by transition metals and endotoxins associated with these particles. However, PM2.5 (less than or equal to 2.5 micro m mean aerodynamic diameter) could be more important as a human health risk because this smaller PM has the potential to reach the distal lung after inhalation. In this study, we compared the cytotoxic and proinflammatory effects of Mexico City PM10 with those of PM2.5 using the murine monocytic J774A.1 cell line in vitro. PMs were collected from the northern zone or the southeastern zone of Mexico City. Elemental composition and bacterial endotoxin on PMs were measured. Tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) production by J774A.1 cells was measured in the presence or absence of recombinant endotoxin-neutralizing protein (rENP). Both northern and southeastern PMs contained endotoxin and a variety of transition metals. Southeastern PM10 contained the highest endotoxin levels, 2-fold higher than that in northern PM10. Northern and southeastern PM2.5 contained the lowest endotoxin levels. Accordingly, southeastern PM10 was the most potent in causing secretion of the proinflammatory cytokines TNF-alpha and IL-6. All PM2.5 and PM10 samples caused cytotoxicity, but northern PMs were the most toxic. Cytokine secretion induced by southeastern PM10 was reduced 50-75% by rENP. These results indicate major differences in PM10 and PM2.5. PM2.5 induces cytotoxicity in vitro through an endotoxin-independent mechanism that is likely mediated by transition metals. In contrast, PM10 with relatively high levels of endotoxin induces proinflammatory cytokine release via an endotoxin-dependent mechanism.     

高温及内毒素复合因素对IL-1 βmRNA表达影响

目的 探讨高温和内毒素(LPS)复合因素对RAW 264.7细胞IL-1β mRNA表达的影响.方法 采用体外培养的巨噬细胞系RAW 264.7细胞,分为37,40℃对照组,37,40℃LPS组.用RT-PCR方法检测RAW 264.7细胞IL-1 βmRNA表达.结果 RAW264.7细胞在37和40℃加或不加LPS条件下随着时间的变化IL-1 βmRNA表达各不相同,在37℃条件下,LPS组随着时间的不断延长,IL-1 βmRNA表达不断增强;40 ℃条件下对照组IL-1βmRNA表达亦表现出不断增强,而LPS组IL-1 βmRNA表达表现为先增强后减弱.结论 高温和内毒素复合因素能够下调RAW 264.7细胞IL-1 βmRNA表达,考虑其原因与高温和内毒素复合因素诱导产生的热休克蛋白及该条件下RAW 264.7细胞的大量凋亡有关.     

In vitro effects on macrophages induced by noncytotoxic doses of silica particles possibly relevant to ambient exposure

The RAW 246.7 macrophage cell line was exposed in vitro to aged crystalline silica particles of respirable size for 24 h at a range of doses starting from 15 microg/2 x 10(6) cells, which is a realistic exposure level of macrophages in the airways of ambiently exposed individuals. The particle sample used for the experiments was prepared to mimic some aspects of ambient crystalline silica particles: size distribution, morphology, and surface reactivity. Our purpose was to determine whether a nontoxic quartz load comparable to that of ambient exposure would be able to induce macrophage activation and impairment of the phagocytic ability, factors altering the lung's capacity to deal with increased particle loads (as occurs during high-pollution episodes) or infections and affecting the local and systemic responses through the release of biologically active compounds (cytokines, reactive oxygen species, NO, isoprostanes). Exposure of RAW 264.7 cells to aged silica particles induced macrophage activation (evidenced by the morphological features observed with scanning electron microscopy and by the release of TNF-alpha and IL-6) and impairment of phagocytosis of test particles, even at noncytotoxic doses. The reduction of the phagocytic function of the cells after silica treatment was dose-dependent, as evidenced by an increase of the population of unphagocytic cells, paralleled by a decrease of the actively phagocytizing cell population. We evaluated the oxidative stress induced by aged silica particles, quantifying the peroxidation products (8-isoprostanes) in the culture media of treated cells, and found a strong release at low doses. Isoprostanes are a complex family of compounds which have been used as in vivo markers of lipid peroxidation in human disorders, but that, as far as we know, have never been evaluated in relation to airborne particulate matter exposure. Lipid peroxides are involved in various cellular events in the inflammatory response, and isoprostanes are also supposed to exert important biological actions on airway and pulmonary vascular smooth muscles and on platelets.     

In vitro and in vivo effects of the probiotic Escherichia coli strain M-17: immunomodulation and attenuation of murine colitis

We examined the in vitro and in vivo effects of a probiotic, Escherichia coli strain M-17 (EC-M17), on NF-kappaB signalling, cytokine secretion and efficacy in dextran sulfate sodium (DSS)-induced murine colitis. NF-kappaB signalling was assessed using an NF-kappaB luciferase reporter cell line that was stimulated with TNF-alpha (100 ng/ml). p65 Nuclear binding and cytokine secretion (TNF-alpha, IL-1beta and IL-6) were evaluated using a RAW 264.7 macrophage cell line that was exposed to lipopolysaccharide (LPS; 5 microg/ml). Mice were administered vehicle, EC-M17, metronidazole, or EC-M17 plus metronidazole for 13 d. During the final 6 d, mice also received 2 % DSS. Parameters evaluated included disease activity index (DAI), histology, myeloperoxidase and NF-kappaB p65. EC-M17 dose dependently inhibited TNF-alpha-induced NF-kappaB signalling. At 5 x 109 colony-forming units/ml, EC-M17 inhibited NF-kappaB by >95 %. LPS-induced nuclear p65 binding was significantly inhibited (78 %; P 90 %) the LPS-induced secretion of TNF-alpha, IL-1beta and IL-6. In mice with DSS-induced colitis, EC-M17, metronidazole, and EC-M17 plus metronidazole significantly reduced DAI and colonic histology scores. Both EC-M17 and metronidazole reduced colonic IL-12, IL-6, IL-1beta and interferon-gamma. The combination of EC-M17 plus metronidazole resulted in more substantial cytokine reductions than were found with either treatment alone, and combination therapy significantly (P < 0.05 in both cases) reduced IL-1beta compared with EC-M17 and colonic histology scores compared with metronidazole. Alone, and in combination with metronidazole, EC-M17 improved murine colitis, probably due to an inhibitory effect on NF-kappaB signalling.