Time-Course Of Airway Responsiveness And Inflammatory Mediator Release In Precision-Cut Lung Slices From Cigarette-Smoke-Exposed A/J Mice

Authored by  V Simoen, K Vandevelde , K Jonckers, E Matthijis, M Peck, A Wohlsen

Presented at The British Pharmacological Society     


INTRODUCTION: Chronic obstructive pulmonary disease COPD) is a disease characterized by airflow limitation that is not fully reversible. The airflow limitation is usually progressive and associated with an abnormal inflammatory response of the lung to noxious particles and gases. The chronic inflammatory response leads to structural changes in the airways (airway remodelling) that are often accompanied by an increased sensitivity of airway smooth muscle to non-specific spasmogens. AIM: In this study we investigated the effect of tobacco smoke exposure on the function of intrapulmonary airways and inflammatory mediator release in mice. METHODS: Female A/J mice (n = 5 per time point per group) were exposed to conditioned fresh air (sham; 4 h/day) or to mainstream smoke from the reference cigarette 3R4F (4 h/day at 750 microg/l total particulate matter [TPM]) for 1 month, 5 months, or 5 months + 2 months post-inhalation. At the end of the exposure period, precision-cut lung slices (PCLS) were prepared. Cumulative concentration-response curves to methacholine (10-9 to 10-4 M) were generated and mediator release in response to overnight stimulation with 100 ng/ml lipopolysaccharide (LPS) was assessed for matrix metalloproteinase 9 (MMP-9), tumour necrosis factor alpha (TNFalpha), interleukin-18 (IL-18), and the chemokines CCL3 (macrophage inflammatory protein 1alpha) and CXCL10 (inducible protein-10). RESULTS: Airway responsiveness: a similar pattern of airway responsiveness with similar pEC50 values for methacholine was observed after 1 month (3R4F: 7.1 ± 0.1 vs. Sham: 6.9 ± 0.1) as well as after 5 months inhalation + 2 months post-inhalation (3R4F: 7.1 ± 0.1 vs. Sham: 6.9 ± 0.1). After 5 months, the pattern of the response to methacholine changed in airways exposed to cigarette smoke. Higher concentrations of methacholine were needed to induce bronchoconstriction and the maximum contraction was stronger compared to control airways (98% vs. 89% reduction of total airway area; not statistically significant). Mediator release: after 1 month, mediator release from smoke-exposed and control PCLS in response to LPS was comparable. After 5 months, levels of MMP-9, IL-18, TNFalpha, and CXCL10 were significantly elevated in the supernatant of PCLS from smoke-exposed mice (sham vs. 3R4F; MMP-9: 11.8 ± 1.8 vs. 39.1 ± 8.9 ng/ml [p