Department of Physiology and Anatomy, Nihon University School of Pharmacy, Funabashi, Chiba, Japan.
Airway Disease Section, National Heart and Lung Institute, Imperial College, London, England.
Chest. 2013 Jul;144(1):99-105. doi: 10.1378/chest.12-2610.
RNA virus infections, such as rhinovirus and respiratory syncytial virus, induce exacerbations in patients with COPD and asthma, and the inflammation is corticosteroid refractory. The main aim of this study is to establish a murine model induced by a Toll-like receptor 3 (TLR3) agonist, an RNA virus mimic, and investigate the response to corticosteroid.
A/J mice were given polyinosinic-polycytidylic acid (poly[I:C]), a TLR3 agonist, intranasally, in the presence or absence of cigarette smoke exposure. Inflammatory cell accumulation and C-X-C motif chemokine (CXCL) 1, interferon (IFN), and CXCL10 production in BAL fluid (BALF) were determined by flow cytometry and enzyme-linked immunosorbent assay, respectively, and airway hyperresponsiveness (AHR) to histamine/methacholine was determined by a two-chambered, double-flow plethysmography system. BALB/c and C57BL/6J mice were also used for comparisons.
Intranasal treatment of poly(I:C) significantly induced airway neutrophilia; production of CXCL1, IFN-β, and CXCL10; and necrotic cell accumulation in BALF. It also increased airway responsiveness to histamine or methacholine inhalation. This poly(I:C)-dependent airway inflammation and AHR was not inhibited by the corticosteroid fluticasone propionate (FP) (up to 0.5 mg/mL intranasal), although FP strongly inhibited lipopolysaccharide (TLR4 agonist)-induced airway neutrophilia. Furthermore, cigarette smoke exposure significantly increased TLR3 expression in murine lung tissue and exacerbated poly(I:C)-induced neutrophilia and AHR.
These results suggest that TLR3 stimulation is involved in corticosteroid-refractory airway inflammation in lung, which is enhanced by cigarette smoking, and this may provide a model for understanding virus-induced exacerbations in COPD and their therapy.
鼻病毒和呼吸道合胞病毒等 RNA 病毒感染可使 COPD 和哮喘患者病情恶化，且炎症对皮质类固醇治疗无效。本研究的主要目的是建立一种 Toll 样受体 3（TLR3）激动剂，即 RNA 病毒模拟物诱导的小鼠模型，并研究其对皮质类固醇的反应。
用 TLR3 激动剂聚肌胞苷酸（poly[I:C]）经鼻内给予 A/J 小鼠，并在存在或不存在香烟烟雾暴露的情况下给予。通过流式细胞术和酶联免疫吸附试验分别测定 BAL 液（BALF）中炎性细胞积聚和 C-X-C 基序趋化因子（CXCL）1、干扰素（IFN）和 CXCL10 的产生，通过双室双气流体积描记系统测定组胺/乙酰甲胆碱诱导的气道高反应性（AHR）。还使用 BALB/c 和 C57BL/6J 小鼠进行比较。
鼻内给予 poly（I:C）可显著诱导气道中性粒细胞增多；BALF 中 CXCL1、IFN-β 和 CXCL10 的产生；以及坏死细胞积聚。它还增加了对吸入组胺或乙酰甲胆碱的气道反应性。尽管氟替卡松丙酸酯（FP）（高达 0.5mg/mL 经鼻内）强烈抑制脂多糖（TLR4 激动剂）诱导的气道中性粒细胞增多，但 FP 并不能抑制依赖 poly（I:C）的气道炎症和 AHR。此外，香烟烟雾暴露显著增加了小鼠肺组织中 TLR3 的表达，并加重了 poly（I:C）诱导的中性粒细胞增多和 AHR。
这些结果表明，TLR3 刺激参与了肺中皮质类固醇难治性气道炎症，而香烟烟雾暴露可增强这种炎症，这可能为理解 COPD 中病毒诱导的恶化及其治疗提供一种模型。
