Figure 1.

Lung development and bronchopulmonary dysplasia (BPD). Perinatal and postnatal factors play an important role in the development of BPD. The figure illustrates stages of lung development in mice: (A) canalicular stage; (B) saccular stage; (C) alveolar stage; (D) lung histology in adult mice; (E) new BPD with simplified alveoli and fewer secondary septae in mice exposed to 85% O₂ from day 3 (P3) to day 14 (P14); (F) lung similar to chronic obstructive pulmonary disease (COPD) in adult mice at 9 months following neonatal oxygen exposure. IUGR: intrauterine growth retardation; O₂: oxygen. (Slide magnification—100×; Inset slides—400×; See text for details).