Fig. 4.

Lung morphometry, including the quantifications of alveolar crests (A), number of pulmonary vessels (B), septal thickness (C), arterial medial wall thickness (D), and influx of macrophages (E) and neutrophilic granulocytes (F) was determined on paraffin sections in RA pups injected daily with saline (open bars) or PD123319 (hatched bars) and O₂ pups injected daily with saline (solid bars) or PD123319 (shaded bars): 0.1 mg·kg⁻¹·day⁻¹ until 10 days of age. Values are expressed as means ± SE (N = 10). **P < 0.01 and ***P < 0.001 vs. age-matched O₂-exposed controls. ^ΔΔΔP < 0.001 vs. own RA controls.