Expression of MMP-12 mRNA by in-situ ASMC. Laser capture microdissection was performed to collect ASMC from bronchial biopsy sections (A). MMP-12 mRNA expression was analysed by real-time RT-PCR (B). The data, obtained from 4 normal volunteers, 3 asthma, 3 COPD and 5 chronic cough patients, were normalized to the housekeeping gene 18S rRNA representative of relative MMP-12 mRNA expression (C). Lung tissue was used as a positive control.