4天香烟烟雾暴露联合poly(I:C)刺激对小鼠肺部免疫应答及干扰素表达的影响

目的：探讨短期香烟烟雾暴露联合poly(I:C)刺激对小鼠肺部免疫应答及干扰素表达的影响。方法：BALB/c小鼠随机分为4组：对照组、熏烟组、poly(I:C)组和熏烟联合poly(I:C)组。检测支气管肺泡灌洗液（BALF）中总细胞数及细胞分类计数;普通光镜下观察各组细胞形态;荧光定量PCR检测肺组织细胞因子、趋化因子和干扰素及干扰素刺激基因表达。结果：与对照组相比,熏烟联合poly(I:C)组总细胞数计数、巨噬细胞与中性粒细胞计数明显升高（P<0.05）,且熏烟联合poly(I:C)组巨噬细胞计数高于poly(I:C)组;与poly(I:C)组比较,熏烟联合poly(I:C)组小鼠气道灌洗液巨噬细胞体积较大,呈圆形或不规则形,细胞质较多空泡;与对照组相比,熏烟联合poly(I:C)组小鼠肺组织中性粒细胞趋化因子CXCL1(P<0.05)、CXCL2(P<0.01)和淋巴细胞趋化因子CCL2(P<0.01) mRNA表达升高,肺组织IL-1β、IL-6、TNF-α mRNA表达明显升高（P<0.01）,肺组织IFN-β(P<0.01)、IFN-γ(...     

LPS直接及间接作用致小鼠急性肺损伤模型的建立

目的　呼吸系统的急性炎症所致的急性肺损伤（ALI）是临床常见的急症、重症,也是目前实验研究的热点。在对其发病机制和治疗手段的探讨过程中,动物模型的有效建立极其重要。 方法　本实验比较了气道内直接滴入和腹腔注射给入两种LPS给入方式,通过组织学病理评价、炎症细胞的细胞学反应,炎症反应细胞分泌物蛋白水平的变化等炎症反应指标,评价了LPS两种不同的给入方式对小鼠急性肺损伤（ALI）模型建立的有效性。 结果　组织学水平显示,气道内直接滴入LPS肺组织炎性细胞浸润的病理改变较腹腔注射LPS组更明显,肺损伤的组织学病理改变也更明显;细胞学水平,气道内直接给入LPS组肺泡灌洗液可见较多中性粒细胞渗出,而腹腔注射LPS组肺泡灌洗液中性粒细胞渗出少,与腹腔注射生理盐水组无差别;细胞因子水平,气道内直接滴入LPS肺组织组肺泡灌洗液蛋白水平明显升高,高于生理盐水对照组和腹腔注射LPS组。 结论 气道内直接滴入LPS是一种有效的小鼠急性肺损伤模型制备方法,可通过LPS的直接气道内分散和刺激至直接肺损伤。     

脂多糖对呼吸道合胞病毒感染小鼠气道炎症及气道高反应性的影响及其机制研究

目的探讨脂多糖(LPS)对呼吸道合胞病毒(RSV)感染小鼠的气道炎症及气道高反应性的影响及其机制。方法将6~8周龄雌性Balb/c小鼠分为4组:对照组、LPS组、RSV组及RSV+LPS组,于首次处理后第7天收取肺组织、肺泡灌洗液标本,QPCR检测肺组织病毒拷贝数,计数肺泡灌洗液(BALF)中细胞总数及分类计数,HE染色观察肺部病理损伤,肺功能测定AHR,Western blot检测TRIF和MyD88蛋白表达,ELISA检测BALF中IFN-γ、KC、IL-1β、IL-6质量浓度。结果 RSV+LPS组病毒拷贝数与RSV组基本一致。RSV+LPS组BALF中细胞总数较LPS组、RSV组增加,且RSV组以淋巴细胞为主,RSV+LPS组以中性粒细胞为主。LPS组、RSV组、RSV+LPS组肺组织炎症及评分均较对照组明显增高。RSV+LPS组AHR较RSV组、LPS组增高。RSV+LPS组肺组织中TRIF表达较LPS组、RSV组增高,各组MyD88基本无变化。RSV组BALF中IFN-γ明显增高,RSV+LPS组KC明显增高,IL-1β、IL-6各组基本无变化。结论 LPS刺激可通过TRIF-KC途径加重RSV感染小鼠气道炎症及AHR。     

地塞米松减轻过敏性哮喘模型小鼠气道炎性反应

目的 观察地塞米松(DEX)对过敏性哮喘模型小鼠气道炎性的影响并探讨相关机制。方法 将小鼠随机分为对照组、哮喘组、地塞米松组。哮喘组小鼠于实验第0、7、14天皮下注射卵清蛋白(OVA)/氢氧化铝混合液,第21、22天1%OVA混悬液雾化吸入20 min;地塞米松组在哮喘组基础上于每次雾化吸入前3 h地塞米松(2 mg/kg)腹腔注射。末次雾化结束测定小鼠气道阻力,24 h后收集肺泡灌洗液(BALF),Wright-Giemsa染色后行细胞分类计数;ELISA测定BALF中IL-6、IL-18和IL-1β等浓度;免疫组织化学法(IHC)检测肺组织NLRP3、IL-1β蛋白表达,HE染色观察肺组织病理。结果 与对照组比较,哮喘组小鼠气道高反应性(AHR)明显增高;BALF中嗜酸性粒细胞、中性粒细胞等炎性细胞数量明显增加;IL-5、IL-6、IL-18和IL-1β表达均升高(P<0.01);肺组织NLRP3、IL-1β蛋白表达增强。与哮喘组比较,地塞米松组小鼠AHR显著降低,BALF中炎性细胞总数、嗜酸性粒细胞、中性粒细胞均明显减少(P<0.01),IL-5、IL-6、IL-18...     

白藜芦醇通过减弱中性粒细胞迁移和浸润改善LPS诱导的急性肺损伤

目的：探究白藜芦醇（RSV）通过减弱中性粒细胞迁移和浸润改善脂多糖（LPS）诱导的急性肺损伤（ALI）。方法 ：将BALB/c小鼠随机分为对照组、RSV组、模型组及模型+RSV组（LPS+RSV）,模型组和LPS+RSV组采用LPS诱导小鼠ALI模型,RSV组和LPS+RSV组以40 mg/kg RSV灌胃,连续灌胃7 d。末次给药后,收集小鼠支气管肺泡灌洗液（BALF）,检测BALF中白细胞、中性粒细胞和蛋白含量,评估肺组织髓过氧化物（MPO）活性,H-E染色观察肺组织病理损伤,检测肺组织和BALF中炎症细胞因子、趋化因子的表达。体外培养中性粒细胞,分别以1μg/mL LPS、1μg/mL RSV处理细胞,流式细胞术检测中性粒细胞凋亡、趋化因子受体（CXCR2、Mac-1）表达,活性氧荧光探针（DCFH-DA）检测细胞内活性氧（ROS）水平,评估中性粒细胞趋化性和迁移能力,免疫印迹检测核因子NF-κB p65磷酸化水平。结果：与模型组比较,LPS+RSV组BALF中细胞总数、中性粒细胞数、蛋白量、TNF-α、IL-6及CXCL2表达降低,肺组织MPO活性、TNF-α、IL-1β、IL...     

Th17淋巴细胞在哮喘小鼠气道炎症中的初步研究

目的:初步探索Th17细胞及其分泌的炎症介质在哮喘小鼠气道炎症中的作用机制。方法:20只小鼠随机均分为哮喘组和正常对照组。哮喘组用卵白蛋白(OVA)致敏与激发建立小鼠哮喘模型。正常对照组致敏与激发均以生理盐水代替。HE染色观察小鼠气道及肺组织病理变化;光学显微镜下观察小鼠支气管肺泡灌洗液(BALF)中细胞分类及计数;酶联免疫吸附试验(ELISA)检测小鼠BALF上清中IL-4、IL-5、IL-13、IFN-γ及IL-17的含量,流式细胞技术(FCM)检测小鼠外周血Th1、Th2及Th17淋巴细胞占CD4+T淋巴细胞百分率情况。结果:哮喘组小鼠BALF中细胞总数和中性粒细胞、嗜酸性粒细胞、淋巴细胞百分率均显著高于对照组(P<0.05),BALF上清中IL-4、IL-5、IL-13及IL-17的水平显著增高(P<0.05),而IFN-γ差异无统计学意义(P>0.05),外周血Th2、Th17细胞明显增高(P<0.05),而Th1细胞无明显变化。结论:Th17细胞及其分泌的炎症介质可促进中性粒细胞及嗜酸性粒细胞在气道内聚集,加重哮喘气道炎症,可能与哮喘气道重塑密切相关。     

慢性尘螨暴露诱导小鼠气道Th1炎症相关的气道重塑

目的:观察慢性尘螨变应原暴露对小鼠气道变应性炎症及重构的影响。方法:采用α平滑肌肌动蛋白启动子驱动的Cre重组酶(α-SMA-Cre)与R26R双转基因报告小鼠,尘螨连续滴鼻60 d后测定气道阻力;肺泡灌洗并分类计数;分离肺组织并提取肺组织蛋白;制备病理组织切片;分离培养脾脏淋巴细胞。结果:慢性尘螨暴露组小鼠气道阻力明显升高(P0.01),肺泡灌洗液(BALF)中细胞总数和淋巴细胞比例显著高于正常对照组(P0.01),肺组织HE染色示:慢性尘螨暴露组小鼠气道上皮细胞炎症水肿,小血管周围淋巴细胞浸润,未见嗜酸粒细胞。X-gal染色显示:尘螨暴露组气道平滑肌细胞及上皮下肌纤维母细胞明显增生,相应Western blotting结果显示α平滑肌肌动蛋白(α-SMA)表达明显增多。尘螨暴露组肺匀浆上清γ干扰素(IFN-γ)较正常对照组升高(P0.01),白细胞介素-4(IL-4)水平两者间没有显著差异(P0.05)。流式细胞检测显示尘螨暴露组分泌IFN-γ的CD4+Th1细胞较正常对照组增多。结论:慢性尘螨气道暴露诱导了Th1炎症,与气道重构和气道高反应性密切相关。     

二甲双胍对小鼠急性肺损伤的保护作用及可能机制研究

目的:探讨二甲双胍对脂多糖(LPS)诱导的小鼠急性肺损伤的保护作用及可能的机制。方法:体重20～25 g的小鼠15只随机分3组:①对照组(Con):气管内滴注PBS;②LPS模型组(LPS):气管内滴注1 mg/ml LPS 60μl,作用24 h;③二甲双胍治疗组(Met+LPS):于滴注LPS前0.5 h给予二甲双胍(250 mg/kg)腹腔注射,再气管内滴注LPS作用24 h;观察各组小鼠肺组织病理学变化,肺泡灌洗液中细胞总数及中性粒细胞比例变化,测定肺组织匀浆内丙二醛(MDA)含量和SOD活力变化。Western blot方法检测肺组织中SOD1变化。结果:在LPS刺激的小鼠模型中,肺泡灌洗液中细胞总数及中性粒细胞比例明显增高,肺组织内MDA含量显著升高,SOD活力明显降低。而以二甲双胍预处理小鼠可明显抑制LPS诱发的上述变化,同时二甲双胍预处理小鼠肺组织SOD1的表达明显增加。结论:二甲双胍可对LPS诱导的急性肺损伤发挥保护作用,这种保护作用可能与上调SOD1的表达有关。     

小鼠克雷白杆菌肺炎模型的建立及检测

目的:研究有效建立小鼠克雷白杆菌肺炎模型的方法并进行相关炎症因子检测。方法:构建动物模型,C57小鼠随机分为对照组和模型组,应用气管内注射肺炎克雷白杆菌(106cfu,20#l)的方法建立肺炎模型,感染后24 h,观察小鼠一般状态;收集肺泡灌洗液、分离肺组织,大体观察;肺组织切片HE染色观察两组小鼠炎症情况;肺泡灌洗液进行中性粒细胞计数,肺泡灌洗液和肺组织MPO检测的方法来比较两组小鼠中性粒细胞浸润情况;应用实时定量PCR、Western blot对两组小鼠相关炎症因子进行检测。结果:和对照组相比,模型组小鼠出现明显喘息,寒颤以及竖毛;肺部出现明显的充血、水肿;HE染色显示模型组肺泡壁增厚,大量炎症细胞浸润;模型组肺泡灌洗液中性粒细胞的数量明显高于对照组(P<0.05);模型组支气管肺泡灌洗液和肺组织中MPO表达水平均明显高于对照组(P<0.05);实时定量PCR、Western blot结果均表明模型组小鼠肺组织中炎症因子较对照组明显升高。结论:利用气管内注菌建立小鼠克雷白肺炎模型的方法确实可靠,该模型可用于细胞因子及其受体与克雷白杆菌肺炎关系的研究。     

Thl7淋巴细胞在哮喘小鼠气道炎症中的初步研究

目的:初步探索Th17细胞及其分泌的炎症介质在哮喘小鼠气道炎症中的作用机制.方法:20只小鼠随机均分为哮喘组和正常对照组.哮喘组用卵白蛋白(OVA)致敏与激发建立小鼠哮喘模型.正常对照组致敏与激发均以生理盐水代替.HE染色观察小鼠气道及肺组织病理变化;光学显微镜下观察小鼠支气管肺泡灌洗液(BALF)中细胞分类及计数;酶联免疫吸附试验(ELISA)检测小鼠BALF上清中IL-4、IL-5、IL-13、IFN-γ及IL-17的含量,流式细胞技术(FCM)检测小鼠外周血Th1、Th2及Th17淋巴细胞占CD4+T淋巴细胞百分率情况.结果:哮喘组小鼠BALF中细胞总数和中性粒细胞、嗜酸性粒细胞、淋巴细胞百分率均显著高于对照组(P<0.05),BALF上清中IL-4、IL-5、IL-13及IL-17的水平显著增高(P<0.05),而IFN-γ差异无统计学意义(P>0.05),外周血Th2、Th17细胞明显增高(P<0.05),而Th1细胞无明显变化.结论:Th17细胞及其分泌的炎症介质可促进中性粒细胞及嗜酸性粒细胞在气道内聚集,加重哮喘气道炎症,可能与哮喘气道重塑密切相关.     

NF-κB在大鼠急性肺损伤模型肺组织中的表达及N-乙酰半胱氨酸的影响

目的 :检测NF κB在LPS诱导的急性肺损伤 (ALI)肺组织中的表达 ,以及N 乙酰半胱氨酸 (NAC)对ALI的抑制作用。方法 :采用免疫组化染色 (ABC法 )和Westernblot,检测NF κB在急性肺损伤大鼠气道和肺组织中的表达 ,以及NAC干预后活性NF κB表达的变化。结果 :正常对照组大鼠气道黏膜上皮和肺间质中 ,仅见少量散在的NF κB核阳性细胞 ;而LPS诱导ALI后 ,气道黏膜、肺间质、肺泡腔及血管内皮细胞中NF κB核阳性的细胞明显增多 (P <0 .0 1)。NF κB核阳性反应细胞主要为气道黏膜上皮细胞、浸润的炎症细胞、肺泡上皮细胞和血管内皮细胞。NAC治疗组NF κB核阳性细胞较LPS诱导的ALI组及对照组均明显减少 (P <0 .0 1)。Westernblot的结果显示 ,LPS诱导的ALI后不同时间点 ,NF κB的表达不同 ,于急性肺损伤 3h达高峰。各时间点NF κB的表达均较正常对照组高。结论 :LPS诱发的大鼠急性肺损伤的气道和肺组织内NF κB的表达增加 ,肺组织内的多数细胞参与了NF κB的激活。NAC可通过抑制NF κB的激活减轻急性肺损伤的炎症程度     

Exposure to systemic prednisolone for 4 hours reduces ex vivo synthesis of GM-CSF by bronchoalveolar lavage cells and blood mononuclear cells of mild allergic asthmatics

BACKGROUND: In acute severe asthma, the earliest clinical effects of glucocorticosteroids occur from 4 to 5 h after systemic administration, but the mechanisms are unclear. In persistent asthma, corticosteroids are thought to suppress airway inflammation by modulating the expression of adhesion molecules, enzymes, and leucotactic cytokines, including granulocyte-macrophage colony stimulating factor (GM-CSF). GM-CSF is also overexpressed in the airways of symptomatic asthmatics. OBJECTIVES: To examine the early effects of systemic corticosteroids on cytokine expression, we investigated whether ex vivo synthesis of GM-CSF is suppressed in the bronchoalveolar lavage (BAL) cells and peripheral blood mononuclear cells (PBMCs) of normal and mild allergic asthmatic subjects obtained 4 h after a single intravenous dose of prednisolone. METHODS: In a randomized, double-blind, placebo-controlled study, BAL cells and PBMCs were obtained from mild atopic asthmatic patients (n = 9) and normal subjects (n = 9) 4 h after an intravenous bolus dose of 80 mg prednisolone, and cultured for 0-18 h in the presence or absence of lipopolysaccharide (LPS; 10 microg/mL). Enzyme immunoassay was used to assess GM-CSF levels in BAL cell and PBMC culture supernatants, and in BAL fluid. RESULTS: After placebo, GM-CSF synthesis tended to be higher in BAL cells from asthmatics than in normals. LPS stimulation significantly increased median (interquartile range) GM-CSF synthesis by BAL cells ex vivo from 16.4 (23 to 74) to 35.8 (3-148) pg/106 cells in normals (P < 0.05), and from 59 (9 to 204) to 134 (24-288) pg/106 cells in asthmatics (P < 0.01). After intravenous prednisolone, the rise in GM-CSF production induced in BAL cells by LPS was completely abolished in both subject groups. In PBMCs of placebo-treated asthmatics (but not normals), LPS stimulated median GM-CSF synthesis from 164 (110 to 300) to 314 (235-485) pg/106 cells (P = 0.02), and this was blocked by intravenous prednisolone. CONCLUSIONS: LPS-stimulated GM-CSF synthesis ex vivo is abolished in BAL cells of mild asthmatic and normal subjects, and in PBMCs of asthmatics, obtained 4 h after a single intravenous dose of prednisolone. Suppression of GM-CSF synthesis in airway and blood leucocytes may contribute to the early clinical efficacy of systemic glucocorticoids in acute allergic asthma.     

Cigarette smoke dissociates inflammation and lung remodeling in OVA-sensitized and challenged mice

We evaluated the effects of cigarette smoke (CS) on lung inflammation and remodeling in a model of ovalbumin (OVA)-sensitized and OVA-challenged mice. Male BALB/c mice were divided into 4 groups: non-sensitized and air-exposed (control); non-sensitized and exposed to cigarette smoke (CS), sensitized and air-exposed (OVA) (50 μg+OVA 1% 3 times/week for 3 weeks) and sensitized and cigarette smoke exposed mice (OVA+CS). IgE levels were not affected by CS exposure. The increases in total bronchoalveolar fluid cells in the OVA group were attenuated by co-exposure to CS, as were the changes in IL-4, IL-5, and eotaxin levels as well as tissue elastance (p<0.05). In contrast, only the OVA+CS group showed a significant increase in the protein expression of IFN-γ, VEGF, GM-CSF and collagen fiber content (p<0.05). In our study, exposure to cigarette smoke in OVA-challenged mice resulted in an attenuation of pulmonary inflammation but led to an increase in pulmonary remodeling and resulted in the dissociation of airway inflammation from lung remodeling.     

Restoring cigarette smoke-induced impairment of efferocytosis in alveolar macrophages

Cigarette smoke has been associated with susceptibility to different pulmonary and airway diseases. Impaired alveolar macrophages (AMs) that are major phagocytes in the lung have been associated with patients with airway diseases and active smokers. In the current report, we show that exposure to second-hand cigarette smoke (SHS) significantly reduced efferocytosis in vivo. More importantly, delivery of recombinant granulocyte–macrophage colony-stimulating factor (GM-CSF) to the alveolar space restored and refurbished the efferocytosis capability of AMs. Exposure to SHS significantly reduced expression of CD16/32 on AMs, and treatment with GM-CSF not only restored but also significantly increased the expression of CD16/32 on AMs. GM-CSF treatment increased uptake and digestion/removal of apoptotic cells by AMs. The latter was attributed to increased expression of Rab5 and Rab7. Increased efferocytosis of AMs was also tested in a disease condition. AMs from GM-CSF-treated, influenza-infected, SHS-exposed mice showed significantly better efferocytosis activity, and mice had significantly less morbidity compared with phosphate-buffered saline-treated group. GM-CSF-treated mice had increased amphiregulin levels in the lungs, which in addition to efferocytosis of AMs may have attributed to their protection against influenza. These results will have great implications for developing therapeutic approaches by harnessing mucosal innate immunity to treat lung and airway diseases and protect against pneumonia.     

Different roles of intracellular and extracellular reactive oxygen species of neutrophils in type 2 diabetic mice with invasive aspergillosis

Diabetic patients have an increased risk of invasive aspergillosis (IA), but the mechanism is still unclear. Reactive oxygen species (ROS) produced by neutrophils play a key role in defense against Aspergillus infection. Since diabetes mellitus affects the production of ROS from neutrophils, the purpose of this study is to investigate whether this effect is related to the susceptibility of diabetic mice to IA. C57BL/6 mice were used to establish type 2 diabetes mellitus (T2DM) model, and IA was induced by airway infection with Aspergillus fumigatus. After infection, the fungal load, neutrophil count and ROS content in the lung tissues of T2DM mice were higher than those in the control mice, and the inflammation of the lung tissue was more serious. After being exposed to hyphae in vitro, compared with the control group, neutrophils in T2DM mice had higher apoptosis rate and intracellular ROS content, as well as lower viability, extracellular ROS content and fungicidal ability. In summary, after T2DM mice are infected with A. fumigatus, the reduction of extracellular ROS produced by neutrophils may lead to a decrease in fungicidal ability, while the increase of intracellular ROS is related to neutrophil and lung tissue damage.     

藤黄酸减轻脂多糖诱导的小鼠急性肺损伤

目的探讨藤黄酸(GA)对脂多糖(LPS)所致小鼠急性肺损伤的保护作用及其机制。方法采用尾静脉注射LPS(4 mg/kg)建立小鼠急性肺损伤模型。实验将小鼠随机分为对照组(control组)、模型组(model组)、藤黄酸组(GA组)和藤黄酸预处理组(GA+LPS组),6 h后测定肺湿/干重比值(W/D);检测髓过氧化物酶(MPO)活性;检测肺泡灌洗液(BALF)中蛋白含量和白细胞计数;ELISA检测肺匀浆中白介素-1β(IL-1β)和肿瘤坏死因子-α(TNF-α)含量。结果模型组小鼠肺W/D、MPO活性、BALF中蛋白含量和白细胞数量均增加,肺组织IL-1β和TNF-α水平升高(均P0.01);藤黄酸预处理可减轻LPS引起的以上指标变化(均P0.05)。结论 GA可减轻LPS诱导的急性肺损伤,其机制可能与降低肺组织IL-1β和TNF-α的含量、抑制中性粒细胞在肺部的聚集和减轻肺部水肿相关。     

An improved technique for repeated bronchoalveolar lavage and lung mechanics measurements in individual rats

Lung function and bronchoalveolar lavage (BAL) fluid are commonly analyzed to assess the severity of lung disease in sacrificed animals. The input impedance of the respiratory system (Z(rs)) was measured and BAL fluid was collected in intubated, anesthetized, mechanically ventilated rats on three occasions 1 week apart. Measurements were performed in control animals (group C), while lung injury was induced in the other group (group LPS) by i.p. injection of lipopolysaccharide (LPS) before the second measurement. The airway resistance (R(aw)), tissue damping (G) and elastance (H) were determined from the Z(rs) spectra. The total cell counts (TC) from 0.3- to 0.4-ml BAL fluid were also determined. R(aw) exhibited no significant change in either group C (-6.7+/-3.6[S.E.]%) or LPS (-0.9+/-3.7%). Reproducible G and H values were obtained in group C (2.5+/-5.3%, -7.0+/-4.4%), while G and H increased in group LPS (18.4+/-6.5%, 14.9+/-13.8%, p<0.05). The changes in TC followed a similar pattern to those observed in G, with no change in group C (-7.9+/-30%), but with a marked increase in group LPS (580+/-456%, p<0.05). The method devised for repeated BAL measurements in another group of rats without intubation and muscle relaxant resulted in similar results in BAL profile. We conclude that longitudinal follow-up of the airway and tissue mechanics and inflammatory cells in the BAL fluid are feasible in rats. The current method allows an early detection of lung injury, even in a relatively mild form.     

Enhanced osteopontin expression in a murine model of allergen-induced airway remodelling

BACKGROUND: Airway remodelling is a central pathophysiological feature of chronic asthma. A wide variety of cytokines and growth factors are likely to be involved in the development of airway remodelling. Osteopontin (OPN) is a cytokine with pro-fibrotic properties; however, its role in airway remodelling in asthma has not been explored. OBJECTIVE: To determine the expression and cellular sources of OPN in a murine model of chronic allergen-induced airway remodelling. METHODS: BALB/c mice were sensitized and exposed to ovalbumin (OVA) or saline inhalations for 5 weeks and killed 24 h after the last inhalation. The following parameters of inflammation and remodelling were assessed: differential cell counts in bronchoalveolar lavage (BAL) fluid lung collagen content (colorimetric biochemical assay) and peribronchial smooth muscle content (immunohistochemistry, followed by image analysis). OPN expression in BAL and lung tissue was determined by PCR and ELISA. The cellular source and distribution of OPN were evaluated by immunohistochemistry and immunofluorescence. RESULTS: OPN expression is up-regulated in lung tissue and in BAL fluid of OVA-treated mice and correlates with collagen content and peribronchial smooth muscle area. In addition, OPN significantly increases collagen deposition in vitro in a murine lung cell line. Cells producing OPN include the airway epithelium and cells of the submucosal inflammatory infiltrate (T cells, eosinophils, and macrophages). Positive staining for OPN was also observed in bronchial tissue from human asthmatic subjects. CONCLUSION: OPN expression in the lungs is increased in a murine model of allergen-induced chronic airway remodelling, suggesting a role for this cytokine in airway remodelling in asthma.