Fig. 7.

A–C: representative histological sections of airways stained with Masson trichrome showing the presence of submucosal deposition of collagen as indicated by the blue staining (arrows) and flattening of the airway epithelium particularly intense after 3 and 6 wk of exposure to ozone. Note also the presence of alveolar damage in the 3- and 6-wk-exposed mice. D–F: representative histological sections of airways stained with Van Gieson stain for the presence of mature collagen in the airway submucosa as indicated by red staining (arrows). There is increased collagen deposition at 3- and 6-wk-exposed mice, with little evidence of collagen in air-exposed mice.