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Ozone exposure induces cough hypersensitivity in mice


Tinglei Li
Shu Zhang
Xuemei Liu
Tianyuan Xin
Yu Chen
Zhe Chen

Abstract

Purpose: To study the influence of O3 exposure on cough sensitivity, airway barrier function and airway inflammation in mice.


Methods: Cough sensitivity was determined in healthy male C57/BL6 mice (aged 8 - 10 weeks) which were exposed to different  concentrations of O3 (0.5 - 2 ppm) for 3 h daily for 9 days. Hematoxylin and eosin (H&E) staining of lung tissues, collection of BALF, and  cell count were carried out. Inflammatory factor levels in pulmonary tissues were determined by enzyme-linked immunosorbent assay  (ELISA), while Western blotting was used to assay TRPA1 and Claudin-1 protein expressions in lung tissues.


Results: After 9 days of mice  exposure to O3, cough sensitivity increased significantly, and TRPA1 protein was increased in pulmonary tissues, with exposure level of 1  ppm resulting in the highest level of TRPA1 protein expression. Claudin-1 expression in lung tissues of mice decreased after O3 exposure,  especially in the groups exposed to O3 levels of 0.5 ppm and 2 ppm. The total cell count in alveolar lavage fluid of mice exposed to O3  was significantly increased (p < 0.05). In addition, O3 exposure increased IL-1α, IL-6 and TNF-α levels, with the most significant increase in  the 0.5 ppm group (p < 0.05). Results from histology revealed that all mice had inflammatory reactions and destruction of lung tissues  after O3 exposure.


Conclusion: Exposure to O3 induces disruption of airway barrier function, infiltration of the airway by inflammatory  cells, and increased secretion of inflammatory factors, thereby resulting in enhanced cough sensitivity.    


Journal Identifiers


eISSN: 1596-9827
print ISSN: 1596-5996