Alveolar derecruitment and collapse induration as crucial mechanisms in lung injury and fibrosis

Idiopathic pulmonary fibrosis (IPF) and bleomycin-induced pulmonary fibrosis are associated with surfactant system dysfunction, alveolar collapse, and collapse induration (irreversible closure). These events play critical but undefined roles in the loss of lung function and disease progression. To quantify how surfactant inactivation leads to lung injury and fibrosis we employed design-based stereology and invasive pulmonary function tests 1, 3, 7, and 14 days (D) following intratracheal bleomycin-instillation in rats. Active surfactant subtypes declined significantly by D1, leading to progressive alveolar closu…