Figure 4

Photomicrographs of histological findings in the animal lungs at 48 h of endotoxin exposure corresponding to 24 h of different gas exposure in control (C) and lipopolysaccharides (LPS)-treated rats. Definition of the subgroups see Fig. 1 legends. All the lungs were fixed by pulmonary arterial perfusion at deflation pressure of 10 cm H₂O for 30 min. Definition and characteristics of subset figures: A, C-Air, well aerated alveoli; B C-ONO, nearly normal alveolar structure alternative with over expanded alveoli; C, C-O, mild atelectatic alveoli; D, C-NO, nearly normal alveolar structure alternative with over expanded alveoli; E, LPS-Air, severe inflammation and edema; F LPS-ONO, severe inflammation and collapsed alternative with over expanded alveoli; G, LPS-O, very severe inflammation and collapse of alveoli; H, LPS-NO, mild collapse of alveoli. Hematoxylin and eosin staining; original magnification ×100.