To study the potential contribution of MMP-9 in the pathogenesis of CF-like lung disease, we assessed levels of secreted MMP-9 protein in BAL supernatant of adult WT, Mmp9-/-, βENaC-Tg and βENaC-Tg/Mmp9-/- mice by gelatin zymography. This evidence concerns the gene MMP9 and lung disorder.