呼吸道合胞病毒感染后期OVA刺激对小鼠气道炎症及AHR的影响

目的研究呼吸道合胞病毒(RSV)感染后期过敏原刺激对小鼠气道炎症及AHR的影响。方法 6~8周龄雌性Balb/c小鼠随机分为Mock组、RSV组、OVA组及R+O组。检测各组小鼠支气管肺泡灌洗液(BALF)中细胞总数及分类计数;苏木精-伊红(HE)染色观察肺部病理损伤;全身体积描述记法检测小鼠气道反应性;ELISA检测BALF中IL-4、IL-5、CXCL10、CCL5、CCL20的水平。结果 R+O组小鼠BALF中炎症细胞总数、巨噬细胞、中性粒细胞及嗜酸性粒细胞分类计数较其他3组均显著增高(P0.05);R+O组小鼠肺组织病理评分及AHR较其他3组亦显著增高(P0.05);BALF中各处理组IL-4、IL-5较Mock组明显增高(P0.05),但处理组之间无显著性差异;R+O组CXCL10水平较其他3组显著升高(P0.05)。结论 RSV感染后期接受OVA刺激可致CXCL10表达增加,进而促使巨噬细胞、中性粒细胞及嗜酸性粒细胞募集,加重小鼠气道炎症及AHR。     

删除嗜酸性粒细胞对支气管哮喘模型小鼠sPLA2-X的影响

目的:探讨支气管哮喘中的分泌型磷脂酶A2-X(sPLA2-X)与嗜酸性粒细胞的关联,为支气管哮喘的治疗提供新的思路与策略。方法:SPF级6～8周雌性BABL/c小鼠48只,分为4组,每组12只,分为健康对照组、哮喘对照组、哮喘/嗜酸性粒细胞删除组及哮喘/嗜酸性粒细胞删除同型对照组。构建小鼠支气管哮喘模型,除健康对照组小鼠于0、7、14 d腹腔注射生理盐水外,其余组小鼠每只分别于0、7、14 d腹腔注射50μg OVA与2 mg氢氧化铝凝胶(溶于200μL生理盐水)。随后根据分组于第21和26天分别进行嗜酸性粒细胞删除抗体(anti-CCR3)及同型对照的腹腔注射及吸入麻醉后的删除抗体滴鼻。于雾化结束后48 h内完成小鼠肺功能检测,每组小鼠一半行全肺灌洗、一半用于肺组织切片HE染色,全血用于检测血清IgE,肺泡灌洗液(BALF)上清液应用于检测细胞因子,肺泡灌洗液细胞用于细胞总数、细胞分类及流式分析。结果:(1)与哮喘对照组相比,哮喘/嗜酸性粒细胞删除组小鼠的气道、肺泡炎症反应显著减轻。(2)哮喘/嗜酸性粒细胞删除组(OVA/anti-CCR3)支气管肺泡灌洗液中嗜酸性粒细胞的百分比显著降低(P0.05)。(3)与哮喘对照组比较,哮喘/嗜酸性粒细胞删除组小鼠气道高反应显著降低(P0.05)。(4)与哮喘对照组相比,哮喘/嗜酸性粒细胞删除组小鼠BALF上清与血清中的sPLA2-X水平均显著降低(P0.05)。(5)与哮喘对照组对比,哮喘/嗜酸性粒细胞删除组小鼠BALF上清中的IL-4、IL-5和IL-13水平显著降低,血清中IgE的水平也显著降低(P0.05)。结论:支气管哮喘中嗜酸性粒细胞与sPLA2-X有重要的关联。     

活菌卡介苗对哮喘小鼠IL-17的调节作用

目的初步探讨活菌卡介苗（BCG）对哮喘小鼠IL-17的调节作用。方法 4周龄雌性Balb/c小鼠30只随机分为A组（对照组）、B组（哮喘组）和C组（BCG干预组）,每组各10只。B、C两组予OVA腹腔注射致敏、OVA雾化诱发哮喘,C组在致敏前14d接种BCG。HE染色观察小鼠肺部病理改变,计数支气管肺泡灌洗液（bronchoalveolar lavage fluid,BALF）中细胞总数并分类,酶联免疫吸附试验（ELISA）检测血清及BALF中白介素-17（IL-17）含量。结果肺组织病理观察显示A组气管周围基本无炎症细胞浸润,B组支气管周围大量炎症细胞浸润,杯状细胞增生,C组炎症较B组减轻。B、C组BALF中细胞总数和嗜酸性粒细胞、淋巴细胞百分率均显著高于对照组（P〈0.01）,而C组嗜酸性粒细胞比例则明显低于B组（P〈0.01）。B、C组小鼠血清、BALF中IL-17含量高于A组（P〈0.01）,而C组则明显低于B组（P〈0.01）。各组小鼠血清及BALF中IL-17水平与BALF中嗜酸性粒细胞呈正相关（P〈0.01）。结论 BCG接种可抑制IL-17的产生,减轻哮喘小鼠气道炎症反应。     

IL-27对哮喘小鼠气道炎症的影响

目的研究IL-27对卵白蛋白(OVA)激发哮喘小鼠气道炎症的影响。方法 24只雌性BALB/c小鼠随机分为生理盐水组、哮喘组及IL-27组,每组8只。应用OVA建立哮喘模型,IL-27组小鼠应用1μgIL-27(溶于50μlPBS中)滴鼻给药,观察3组小鼠肺组织病理改变,计数支气管肺泡灌洗液(BALF)中嗜酸性粒细胞;ELISA法测定小鼠BALF中IL-4和IFN-γ浓度,RT-PCR测定肺组织T-bet mRNA的表达量。结果 IL-27组小鼠肺组织炎症反应明显轻于哮喘组小鼠;IL-27组小鼠BALF中嗜酸性粒细胞计数为(2.21±0.33)×107/L明显低于哮喘组的(12.82±2.17)×107/L(P0.01);IL-27组小鼠BALF中IL-4浓度为(20.4±3.2)μg/L,明显低于哮喘组的(61.3±13.1)μg/L(P0.05);IL-27组小鼠BALF中IFN-γ浓度为(50.3±6.3)μg/L,明显高于哮喘组的(11.1±3.3)μg/L(P0.05);IL-27组小鼠肺组织T-bet mRNA表达量(吸光度积分比值)为(0.268±0.048),明显高于哮喘组的(0.130±0.012)(P0.05)。结论 IL-27可能通过增强T-bet mRNA的表达增强Th1反应,减少BALF中嗜酸性粒细胞数量,进而减轻了哮喘小鼠肺组织炎症反应。     

干扰素-γ质粒基因转染对哮喘小鼠支气管肺泡灌洗液炎症细胞的影响

目的观察气道内干扰素-γ(IFN-γ)基因转染对哮喘小鼠支气管肺泡灌洗液(BALF)嗜酸性粒细胞、中性粒细胞和淋巴细胞的影响.方法 C57BL/6小鼠40只,随机分为4组,每组10只,分别为正常对照组、哮喘组、模型空质粒干预组(空质粒组)和模型干扰素质粒干预组(干扰素组).卵白蛋白(OVA)抗原溶液腹腔注射致敏,滴鼻激发造模.对照组用生理盐水代替OVA;空质粒组和干扰素组分别经鼻滴入空质粒或重组干扰素质粒.观察各组实验小鼠的哮喘症状以及BALF中IFN-γ水平和各类炎症细胞的变化.结果哮喘组BALF中IFN-γ水平比正常对照组显著降低;哮喘小鼠干扰素质粒气道内转导后哮喘症状明显减轻,BALF中IFN-γ水平显著升高,同时嗜酸性粒细胞、中性粒细胞和淋巴细胞显著减少.结论气道内转染干扰素质粒能有效改善哮喘小鼠的症状和气道炎症.     

干扰素-γ质粒基因转染对哮喘小鼠支气管肺泡灌洗液炎症细胞的影响

目的　观察气道内干扰素 -γ(IFN -γ)基因转染对哮喘小鼠支气管肺泡灌洗液 (BALF)嗜酸性粒细胞、中性粒细胞和淋巴细胞的影响 .方法　C5 7BL/ 6小鼠 4 0只 ,随机分为 4组 ,每组 10只 ,分别为正常对照组、哮喘组、模型空质粒干预组 (空质粒组 )和模型干扰素质粒干预组 (干扰素组 ) .卵白蛋白 (OVA)抗原溶液腹腔注射致敏 ,滴鼻激发造模 .对照组用生理盐水代替OVA ;空质粒组和干扰素组分别经鼻滴入空质粒或重组干扰素质粒 .观察各组实验小鼠的哮喘症状以及BALF中IFN -γ水平和各类炎症细胞的变化 .结果　哮喘组BALF中IFN -γ水平比正常对照组显著降低 ;哮喘小鼠干扰素质粒气道内转导后哮喘症状明显减轻 ,BALF中IFN -γ水平显著升高 ,同时嗜酸性粒细胞、中性粒细胞和淋巴细胞显著减少 .结论　气道内转染干扰素质粒能有效改善哮喘小鼠的症状和气道炎症 .     

雷公藤甲素对中性粒细胞性哮喘小鼠肺泡灌洗液中WBC和EOS的影响

目的:初步探讨雷公藤甲素对中性粒细胞哮喘小鼠肺泡灌洗液中WBC和EOS的影响。方法:采用卵清蛋白(OVA)联合脂多糖(LPS)致敏方法建立支气管哮喘小鼠模型,BALB/c小鼠32只随机分为中性粒细胞性哮喘组(NA组)、中性粒细胞性雷公藤甲素干预组(TLN组)、中性粒细胞性地塞米松干预组(DXN组)和正常对照组(NC组)各8只,血球计数板计算各组小鼠肺泡灌洗液(BALF)中WBC及EOS的总数目;涂片瑞士染色查看炎症细胞浸润情况。结果:DXN组、TLN组小鼠BALF中WBC总数、EOS总数及其浸润情况均较NA组明显下降(均P0.05),但均明显高于NC组(均P0.05),DXN组上述各指标均较TLN组明显升高(均P0.05)。结论:雷公藤甲素可减少BALF中WBC及EOS总数,抑制肺部WBC、EOS浸润,缓解中性粒细胞性哮喘气道炎症。     

金黄色葡萄球菌肠毒素对小鼠慢性哮喘模型的抗炎作用

目的：用金黄色葡萄球菌肠毒素A（SEA）和肠毒素B（SEB）干预幼年小鼠,观察它们对小鼠慢性哮喘气道炎症的影响以及对气道内相关细胞因子水平的调节作用。方法：实验组中BALB/c小鼠在出生后1周开始腹腔注射0.1 mL SEA或SEB（浓度1 mg/L）,隔天注射,共7次。其它小组注射相同剂量生理盐水对照。BALB/c 小鼠出生后4周建立哮喘模型,实验组和模型组分别在0、7和14 d用卵白蛋白（OVA）腹腔注射致敏,在28 d开始隔天OVA雾化激发哮喘,共7次,末次激发后24-48 h内取支气管肺泡灌洗液（BALF）,进行嗜酸性粒细胞和总白细胞计数,其余BALF离心-70 ℃冻存检测细胞因子,固定肺组织做病理切片分析。结果:SEA组和SEB组小鼠肺组织炎症反应轻于模型组,BALF中嗜酸性粒细胞数量少于模型组 (P＜0.05);SEA、SEB组BALF中Th1细胞因子干扰素-γ（IFN-γ）高于模型组(P＜0.05);而Th2细胞因子白细胞介素-4（IL-4）、白细胞介素-5（IL-5）和嗜酸性粒细胞趋化因子（eotaxin）均低于模型组(P＜0.01)。结论:早期感染 SEA、SEB可以减少小鼠慢性哮喘支气管肺泡灌洗液中嗜酸性粒细胞的数量,可能通过调节Th1/Th2细胞因子比值减轻气道中的哮喘炎症反应。     

雾化吸入灭活草分支杆菌减轻哮喘小鼠气道炎症及对Toll样受体2表达的影响

目的研究雾化吸入灭活草分支杆菌对支气管哮喘小鼠气道炎症及肺组织细胞因子分泌的影响,探讨Toll样受体2(TLR2)表达在雾化吸入灭活草分支杆菌防治支气管哮喘中的作用。方法将24只雄性Balb/c小鼠按随机数字表法分为3组,每组8只:正常对照组(A)、哮喘模型组(B)、干预组(C)。卵清蛋白(OVA)致敏制小鼠支气管哮喘模型。C组在每次卵蛋白激发前给予雾化吸入草分枝杆菌治疗,每天1次。各组动物处死后提取肺组织和支气管肺泡灌洗液(BALF)。进行病理HE染色、AB-PAS染色观察支气管肺炎症和气道粘液分泌情况,并行半定量分析。BALF中炎症细胞计数,检测BALF中IL-4、IL-10、IFN-γ水平。实时定量PCR检测肺组织TLR2 mRNA表达水平。结果干预组BALF中IL-4分泌减少,IL-10、IFN-γ增加(P<0.05),BALF中嗜酸性粒细胞比例低于模型组,气道炎症病变较模型组减轻,肺组织TLR2 mRNA表达水平较模型组显著升高(P<0.05)。结论吸入草分枝杆菌能减轻支气管哮喘小鼠气道炎症,其效应与调节肺内细胞因子分泌有关。草分枝杆菌可能通过上调TLR2基因的表达调节支气管哮喘的免疫失衡。     

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.     

Recombinant Mycobacterium bovis BCG producing IL-18 reduces IL-5 production and bronchoalveolar eosinophilia induced by an allergic reaction

BACKGROUND: Allergic reactions occur through the exacerbated induction of a Th2 cell type expression profile and can be prevented by agents favoring a Th1 profile. Bacillus Calmette-Guérin (BCG) is able to induce high IFN-gamma levels and has been shown to decrease experimentally induced allergy. The induction of IFN-gamma is mediated by interleukin (IL)-12 known to be secreted upon mycobacterial infections and can be enhanced by IL-18 acting in synergy with IL-12. OBJECTIVE: We evaluated the ability of a recombinant BCG strain producing IL-18 (rBCG) to modify the Th2 type responses in a murine model of ovalbumin (OVA)-dependent allergic reaction. METHODS: Mice were injected intraperitoneally or intranasally with OVA at days 0 and 15 and exposed to an OVA aerosol challenge at days 29, 30, 31 and 34. At days 0 and 15, two additional groups of mice received OVA together with 5 x 10(6) colony forming units of either rBCG or nonrecombinant BCG. RESULTS: A time-course analysis of OVA-specific immunoglobulin (Ig)E, IgG1 and IgG2a levels indicated no significant difference between the three groups of mice. However, following in vitro stimulation with OVA, lymph node cells from rBCG-treated mice produced less IL-5 and more IFN-gamma than those of mice injected with nonrecombinant BCG. In addition, 48 h after the last OVA challenge, a strong reduction of bronchoalveolar eosinophilia was found in the rBCG-injected mice compared to the nontreated or nonrecombinant BCG-treated groups. CONCLUSION: These results indicate that the production of IL-18 by rBCG may enhance the immunomodulatory properties of BCG that suppress pulmonary Th2 responses and, in particular, decrease airway eosinophilia.     

Creatine supplementation exacerbates allergic lung inflammation and airway remodeling in mice

Creatine supplement is the most popular nutritional supplement, and has various metabolic functions and sports medicine applications. Creatine supplementation increases muscle mass and can decrease muscular inflammation. Some studies have also suggested a beneficial role of creatine supplementation on chronic pulmonary diseases such as chronic obstructive pulmonary disease and cystic fibrosis. Among athletes, the prevalence of asthma is high, and many of these individuals may be taking creatine. However, the effects of creatine supplementation on chronic pulmonary diseases of allergic origin have not been investigated. In the present study, we analyzed the effects of creatine supplementation on a model of chronic allergic lung inflammation. Thirty-one Balb/c mice were divided into four groups: control, creatine (Cr), ovalbumin (OVA), and OVA+Cr. OVA and OVA+Cr groups were sensitized with intraperitoneal injections of OVA on Days 0, 14, 28, and 42. OVA challenge (OVA 1%) and Cr treatment (0.5 g/kg/d) were initiated on Day 21 and lasted until Day 53. We determined the index of hyperresponsiveness, the serum levels of OVA-specific immunoglobulin (Ig)E and IgG(1), and the total and differential cell counts in bronchoalveolar lavage fluid. We also quantified airway inflammation, and the airway density of IL-4+, IL-5+, IL-2+, IFN-gamma+, and insulin-like growth factor (IGF)-1+ cells, collagen and elastic fibers, and airway smooth muscle thickness. Our results showed that creatine in OVA-sensitized mice increased hyperresponsiveness; eosinophilic inflammation; airway density of IL-4+, IL-5+, and IGF-1 inflammatory cells; airway collagen and elastin content; and smooth muscle thickness. The results show that creatine supplementation exacerbates the lung allergic response to OVA through a T helper cell type 2 pathway and increased IGF-1 expression.     

Respiratory syncytial virus infection does not increase allergen-induced type 2 cytokine production, yet increases airway hyperresponsiveness in mice

Severe respiratory syncytial virus (RSV)-induced disease is associated with childhood asthma and atopy. We combined murine models of allergen-sensitization and RSV infection to explore the interaction of allergic and virus-induced airway inflammation and its impact on airway hyperresponsiveness (AHR). We found that RSV infection during ova-sensitization (OVA/RSV) increased and prolonged AHR compared to mice only RSV-infected (RSV) or ova-sensitized (OVA). AHR is known to be associated with an increase in Type 2 cytokines (IL-4, IL-5, and IL-13) in allergen-sensitized mice. Therefore, we hypothesized that RSV-induced enhancement of AHR was a result of potentiating the Type 2 cytokine profile promoted by ova-sensitization. Surprisingly, we found that Type 2 cytokines induced by ova-sensitization were not increased by RSV infection despite the increase in AHR, and in some cases were diminished. RNAse protection assay revealed no difference in IL-4 and IL-5 mRNA levels between the OVA and OVA/RSV groups, and IL-13 mRNA was significantly decreased in the OVA/RSV mice compared to the OVA group. Flow cytometric analysis of Type 2 cytokines demonstrated the same frequency of IL-4 and IL-5 production in lung-derived T lymphocytes from the OVA/RSV and OVA groups. Direct cytokine ELISA measurements of lung supernatant showed the level of IL-13 was significantly decreased in the OVA/RSV group compared to OVA mice, while there was no difference in either IL-4 or IL-5 between these two groups. These data indicate that the enhanced and prolonged AHR caused by the interaction of allergic airway inflammation and virus-induced immune responses is a complex process that can not be explained simply by augmented production of Type 2 cytokines.     

Status of Stat3 in an ovalbumin-induced mouse model of asthma: analysis of the role of Socs3 and IL-6

BACKGROUND: Stat3, Socs3 and cytokines play an integral role in the coordination and persistence of inflammation. However, a clear understanding of the role played by the Stat3/IL-6 and Socs3 pathway in airway inflammation is lacking. We report the alteration in the status of expression and activation of Stat3 by ovalbumin (OVA), and establish its relationship with Socs3 and IL-6 in the lungs of mice with eosinophilic pulmonary inflammation and airway hyperresponsiveness. METHODS: Alterations in the expression of Stat3, Socs3 and IL-6 were determined in a murine model of asthma, where Balb/c mice were sensitized and challenged with OVA (OVA/OVA) and compared with control mice sensitized and challenged with saline (SAL) (SAL/SAL) mice. The OVA/OVA mice were characterized by a moderate increase in methacholine-induced specific airway resistance, the presence of 150 microg/ml of OVA-specific IgG and 8.93 microg/ml OVA-specific IgE antibody and elevated levels of eosinophils and Th2 cytokines (IL-4 and IL-5) in the bronchoalveolar lavage fluid. In contrast SAL/SAL mice had low eosinophils, IL-4 and IL-5 and no OVA-specific IgG and IgE antibodies in the BALF. Stat3 and Socs3 expression profiles were monitored in OVA/OVA and Stat3- and Socs3-silenced OVA/OVA mice. Furthermore, expression of IL-6 in Stat3- and Socs3-silenced mice and the exogenous effect of IL-6 on Stat3 were studied. RESULTS: The results show that expression and activation of Stat3 mRNA and proteins are significantly low in lung of OVA/OVA mice in comparison to SAL/SAL mice following OVA challenge. An increased pool of Socs3 mRNA is observed in OVA/OVA mice with or without OVA challenge and in SAL/SAL mice 24 h after OVA challenge. Transient in vivo blocking of Socs3 gene by Socs3 siRNA restores the expression of IL-6 mRNA and protein in OVA/OVA mice, and nasal administration of recombinant IL-6 to OVA/OVA mice enhanced Stat3 mRNA expression. CONCLUSIONS: Our data suggest that airway inflammation is associated with low expression of Stat3 and IL-6 and overexpression of Socs3 genes in a mouse model of asthma. Furthermore, IL-6 is under the influence of the Socs3 gene and may contribute to the negative regulation of Stat3 via IL-6 following a challenge with an allergen during the development of asthma.     

Effects of aerobic exercise on chronic allergic airway inflammation and remodeling in guinea pigs

We evaluated the effects of aerobic exercise (AE) on airway inflammation, exhaled nitric oxide levels (ENO), airway remodeling, and the expression of Th1, Th2 and regulatory cytokines in a guinea pig asthma model. Animals were divided into 4 groups: non-trained and non-sensitized (C), non-sensitized and AE (AE), ovalbumin-sensitized and non-trained (OVA), and OVA-sensitized and AE (OVA+AE). OVA inhalation was performed for 8 weeks, and AE was conducted for 6 weeks beginning in the 3rd week of OVA sensitization. Compared to the other groups, the OVA+AE group had a reduced density of eosinophils and lymphocytes, reduced expression of interleukin (IL)-4 and IL-13 and an increase in epithelium thickness (p<0.05). AE did not modify airway remodeling or ENO in the sensitized groups (p>0.05). Neither OVA nor AE resulted in differences in the expression of IL-2, IFN-γ, IL-10 or IL1-ra. Our results show that AE reduces the expression of Th2 cytokines and allergic airway inflammation and induces epithelium remodeling in sensitized guinea pigs.     

Interleukin-18-deficient mice exhibit diminished chronic inflammation and airway remodelling in ovalbumin-induced asthma model

Interleukin (IL)-18, which is produced by activated monocytes/macrophages and airway epithelial cells, is suggested to contribute to the pathophysiology of asthma by modulating airway inflammation. However, the involvement of IL-18 on modulating chronic airway inflammation and airway remodelling, which are characterized in a refractory asthma model exposed to long-term antigen, has not been investigated sufficiently. We examined the role of IL-18 in chronic airway inflammation and airway remodelling by long-term antigen exposure. IL-18-deficient and C57BL/6-wild-type mice were sensitized by ovalbumin (OVA) and were then exposed to aerosolized OVA twice a week for 12 weeks. We assessed airway inflammation by assessing the infiltration of cells into the airspace and lung tissues, and airway remodelling by airway mucus expression, peribronchial fibrosis and smooth muscle thickness. In IL-18-deficient mice, when exposed to OVA, the total cells and neutrophils of the bronchoalveolar lavage fluid (BALF) were diminished, as were the number of infiltrated cells in the lung tissues. IL-18-deficient mice exposed to OVA after 12 weeks showed significantly decreased levels of interferon (IFN)-gamma, IL-13 and transforming growth factor (TGF)-beta1 in the BALF. The airway hyperresponsiveness to acetyl-beta-methacholine chloride was inhibited in IL-18-deficient mice in comparison with wild-type mice. In addition, IL-18-deficient mice exposed to OVA had fewer significant features of airway remodelling. These findings suggest that IL-18 may enhance chronic airway inflammation and airway remodelling through the production of IFN-gamma, IL-13 and TGF-beta1 in the OVA-induced asthma mouse model.     

Haemopoietic mechanisms in murine allergic upper and lower airway inflammation

Eosinophil recruitment to the airways, including involvement of haemopoietic eosinophil-basophil progenitors (Eo/B-CFU), is primarily regulated by interleukin-5 (IL-5) and eotaxin. In this study, we investigated the haemopoietic mechanisms in upper and lower airway eosinophilic inflammation. Ovalbumin (OVA) sensitized and challenged BALB/c mice were used to establish isolated upper (UAC), isolated lower (LAC), or combined upper and lower airway (ULAC) inflammation. Airway, blood and bone marrow responses were evaluated in each model. Numbers of airway eosinophils and CD4(+) cells were increased significantly in the nasal mucosa in UAC and ULAC mice, and in the lung tissue in LAC and ULAC groups. Levels of IL-5 and eotaxin were increased significantly in the nasal lavage fluid (NL) in UAC and ULAC mice, and in the bronchoalveolar lavage fluid (BAL) in LAC and ULAC groups. The proportion of IL-5-responsive bone marrow Eo/B-CFU was significantly higher than the control in all treatment groups, but peaked much earlier in the ULAC group. Kinetic studies revealed that IL-5 and eotaxin in NL, BAL and serum peaked between 2 and 12 hr after OVA challenge in ULAC mice, and at 24 hr in UAC mice, related to the timing of maximal progenitor responses. These data support the concept that the systemic mechanisms linking rhinitis to asthma depend on the location and extent of airway allergen exposure.     

Prolonged antigen exposure ameliorates airway inflammation but not remodeling in a mouse model of bronchial asthma.

BACKGROUND: In naive rodents, repeated exposure to aerosolized antigen induces suppression of the Th2 response to the antigen. We hypothesized that more prolonged exposure of established asthma model to antigen aerosols may downregulate asthmatic phenotype. METHODS: After establishing an ovalbumin (OVA)-induced asthma model, mice were further exposed to OVA (prolonged exposure group) or phosphate-buffered saline (positive controls) 3 days per week for 6 weeks. During week 7, the mice of both groups were finally challenged with OVA. RESULTS: Prolonged OVA exposure resulted in marked suppression of serum OVA-specific immunoglobulin E (IgE) antibody levels, eosinophilia of the airway, and airway hyperresponsiveness (AHR). However, airway remodeling characterized by goblet cell hyperplasia and airway fibrosis was observed to the same degree in both groups. These effects were accompanied by diminished production of Th2 cytokines such as interleukin-4 (IL-4), IL-5 and IL-13 in bronchoalveolar lavage fluid (BALF) and cultured supernatant of splenocytes. Furthermore, prolonged exposure markedly increased IL-12 levels in BALF. CONCLUSIONS: Prolonged antigen exposure has inhibitory effects on eosinophilic inflammation, AHR and IgE response to antigen, but not on airway remodeling, presumably via inhibition of Th2 cytokines and increased IL-12 production in the lungs.     

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.     

IL-12p40 is essential for the down-regulation of airway hyperresponsiveness in a mouse model of bronchial asthma with prolonged antigen exposure

Background We previously reported a mouse model of bronchial asthma showing eosinophilic inflammation, but not airway hyperresponsiveness (AHR), after prolonged antigen exposure. This model showed an increase of IL-12 in the lung.
Objective The aim of this study was to investigate the role of IL-12p40 in a murine asthma model with prolonged antigen exposures.
Methods An ovalbumin (OVA)-induced asthma model was first established in wild-type (WT) and IL-12p40-deficient (IL-12p40^−/−) mice. Both strains of mice were further exposed to either OVA (prolonged exposure group) or phosphate-buffered saline (positive control group) 3 days per week for 3 weeks. During week 4, both groups of mice were given a final challenge with OVA.
Results Prolonged antigen exposures resulted in marked suppression of airway eosinophilia in both WT and IL-12p40^−/− mice. However, AHR persisted in IL-12p40^−/− but not in WT mice. There were no significant differences of IL-5, IL-13 or IFN-γ levels in bronchoalveolar lavage fluid between WT and IL-12p40^−/− mice. The hydroxyproline content of the lung and peribronchial fibrosis were, however, significantly increased in IL-12p40^−/− mice.
Conclusion The results suggest that endogenous IL-12p40 is essential for inhibition of AHR and peribronchial fibrosis, but not eosinophilic inflammation, in a murine asthma model with prolonged antigen exposures.