Figure 4

Histological findings of neonatal lungs in the presence of hyperoxia. Photomicrographs of lung tissue from control (C) and hyperoxia-exposed (H) rats at 3, 7, and 14 days. While normal development and alveolarization is seen in the control group, the hyperoxia exposed group shows significant dilatation and expansion of the alveolar ducts and the ventilatory units. The changes are most prominent at day 7 and regress at day 14. (Hematoxylin and Eosin × 10).