Poly I:C Exacerbates Airway Inflammation and Remodeling in Cigarette Smoke-Exposed Mice

Background: Chronic obstructive pulmonary disease (COPD) is a chronic respiratory disorder characterized by chronic inflammation and airway remodeling. Cigarette smoke (CS) and respiratory viruses are major causes of COPD development and exacerbation, but the mechanisms of these compounding factors on inflammation and pathological changes in airway structure still need further investigation. Purpose: This work aimed to investigate the effects and mechanisms of Poly I:C on pathological changes in CS-induced COPD mice, such as airway inflammation and remodeling. Methods: From 1 to 8 weeks, the mice were exposed to CS, Poly I:C, or a combination of both. To compare the pathological changes among different groups over time, the mice were sacrificed at week 4, 8, 16, and 24, then the lungs were harvested to measure pulmonary pathology, inflammatory cytokines, and airway remodeling. Results: Our data revealed that the fundamental characteristics of COPD, such as pulmonary pathological damage, the release of inflammatory mediators, and the remodeling of airway walls, were observed at week 8 in CS-exposed mice and these pathological changes persisted to week 16. Compared with the CS group, the pathological changes, including decreased lung function, inflammatory cell infiltration, alveolar destruction, and airway wall thickening, were weaker in the Poly I:C group. These pathological changes were observed at week 8 and persisted to week 16 in Poly I:C-induced mice. Furthermore, Poly I:C exacerbated lung tissue damage in CS-induced COPD mice. The decreased lung function, airway inflammation and remodeling were observed in the combined group at week 4, and these pathological changes persisted to week 24. Our research indicated that Poly I:C enhanced the expression of p-P38, p-JNK and p-NF-κB in CS-exposed mice. Conclusion: Poly I:C could promote airway inflammation and remodeling in CS-induced COPD mice probably by NF-κB and MAPK signaling.