Tumor Necrosis Factor–α Overexpression in Lung Disease

Rationale: Tumor necrosis factor α (TNF-α) has been implicated as a key cytokine in many inflammatory lung diseases. These effects are currently unclear, because a transgenic mouse overexpressing TNF-α in the lung has been shown in separate studies to produce elements of both emphysema and pulmonary fibrosis. Objectives: We sought to elucidate the phenotypic effects of TNF-α overexpression in a mouse model. Measurements: We established the phenotype by measuring lung impedance and thoracic gas volume, and using micro–computed tomography and histology. Main Results: We found that airways resistance in this mouse was not different to control mice, but that lung tissue dampening, elastance, and hysteresivity were significantly elevated. Major heterogeneous abnormalities of the parenchyma were also apparent in histologic sections and in micro–computed tomography images of the lung. These changes included airspace enlargement, loss of small airspaces, increased collagen, and thickened pleural septa. We also fo...