Fig. 4

Remodeling and fibrosis of the peripheral lung. Of the small airways, the relative expression of α-SMA (stained in green) of smooth muscle to total wall area increased significantly in DEP exposure for 4-wk and 8-wk, respectively (*** p < 0.001, A-B). In the alveolar region, the number of α-SMA positive cells (white arrow head, C) increased significantly post-DEP exposures (*** p < 0.001, D). The fibrosis areas (stained in blue, E) around the small airways also significantly increased following 4-wk and 8-wk DEP exposures, respectively (* p < 0.05, ** p < 0.01, F). The contents of hydroxyproline in lung tissue significantly increased in rats exposed to DEP for 4 weeks and 8 weeks, respectively (** p < 0.01, G). Data were expressed as mean (95% CI). Bars in the immunofluorescent staining images = 50 μm, while bar in the Masson Trichrome staining image = 100 μm. SA: small airways, ns = not significant