HE staining and lung injury score.

<p>A-B: HE staining of a pressure fixed lung of pups held in normoxia (A) or hyperoxia (B) for 7 days of life. In the magnification square, neutrophils are marked by the arrows. C: lung injury score assessing 5 different parameters: neutrophils in alveolar airspace, neutrophils in the interstitial space, hyaline membranes, proteinaceous debris filling the airspace, alveolar septal thickening.