Histology following hyperoxic injury. Hematoxylin-eosin stained lung sections of (a) IGF-1R+/+, and (b) IGF-1Rneo/- mice following 72 h of hyperoxic exposure, illustrating perivascular and peribronchiolar edema as indicated by asterisks. Magnification: 10× objective. Representative histology of lung sections demonstrates (c) focal alveolar hemorrhages (black arrow) and hyaline membrane formation (gray arrow) in IGF-1R+/+ lungs, and (d) minimal lesions in IGF-1Rneo/- mice. Magnification: 40× objective.