Traffic-related air pollution induces non-allergic eosinophilic airway inflammation and cough hypersensitivity in guinea-pigs.

Journal Article (Journal Article)

Background

The pathogenesis and pathophysiology of eosinophilia-related chronic cough such as non-asthmatic eosinophilic bronchitis and cough variant asthma are still not clear.

Objective

This study is to examine the potential role of traffic-related air pollution (TRAP) in eosinophilic inflammation and cough responses.

Methods

Non-sensitized guinea-pigs were exposed to TRAP in an urban traffic tunnel or kept in a filtered air environment for 7 or 14 days. Reflexive cough was measured using citric acid and allyl isothiocyanate (AITC) challenges, respectively. Spontaneous cough counting was determined using audio recording and a waveform analysis. Airway inflammation was evaluated using differential cells in bronchoalveolar lavage fluid (BALF) and lung histopathology. To further elucidate the relationship between airway inflammation and cough hypersensitivity, a subgroup of those exposed for 14 days received a dexamethasone treatment.

Results

Compared to reflexive cough count (mean (95% confidence interval) in 10 minutes) provoked by the AITC challenge for the unexposed animals (3.1 (1.7-4.5)), those were increased significantly following both the 7-day (12.0 (6.8-17.2), P < 0.01) and the 14-day (12.0 (6.4-17.6), P < 0.01) TRAP exposure. The effect provoked by the citric acid challenge was more profound following the 14-day exposure (26.0 (19.5-32.5) vs 3.8 (1.5-6.0) for the control, P < 0.001). TRAP exposures enhanced spontaneous cough events, caused a significant increase of eosinophils and neutrophils in BALF and resulted in a dramatic eosinophilic infiltration in submucosal layer of trachea and bronchus, which can be inhibited significantly by dexamethasone treatment.

Conclusions & clinical relevance

TRAP exposures induced cough hypersensitivity and non-allergic eosinophilic inflammation of airways in guinea-pigs. This study highlights the potential mechanisms of eosinophilia-related chronic cough that can be induced by traffic-related air pollution.

Full Text

Duke Authors

Cited Authors

  • Fang, Z; Huang, C; Zhang, JJ; Xie, J; Dai, S; Ge, E; Xiang, J; Yao, H; Huang, R; Bi, X; Wang, B; Zhong, N; Lai, K

Published Date

  • March 2019

Published In

Volume / Issue

  • 49 / 3

Start / End Page

  • 366 - 377

PubMed ID

  • 30415484

Electronic International Standard Serial Number (EISSN)

  • 1365-2222

International Standard Serial Number (ISSN)

  • 0954-7894

Digital Object Identifier (DOI)

  • 10.1111/cea.13308

Language

  • eng