Figure 4

The typical histopathologic changes of acute lung injury. a, no hyaline membrane formation; b, mild hyaline membrane formed; c, moderate hyaline membrane appeared; d, severe hyaline membrane formed; e, a great number of erythrocytes appeared in the alveolar cavities with alveolar septa thickening; f, severe hyaline formation with alveolar epitheliums swelling (a, b, c, d, e and f were stained with hematoxylin-eosin stain, ×400); g, disappearance of basement membrane (white arrow) and mitochondria swelling of alveolar epithelium (electron microscopy, ×10,000); h, disappearance of basement membrane (white arrow) and hyaline membrane formation (black arrow)(electron microscopy, ×8,000); AE, alveolar epithelium; M, mitochondria.