Representative lung histology. (A) naïve lungs, (B) day 14, (C) day 21, (D) day 35, (E) day 56 and (F) day 225 after intratracheal AdTGF-β1 administration (40×). (G) Fibrotic index (Ashcroft). (G) Hydroxyproline content per mg dry lung. Group comparison was performed using one way ANOVA with Dunnett's multiple comparison test. All values are given as mean, SE, n = 4–6 in each group, * p < 0.05, ** p < 0.01, *** p < 0.001 vs. naïve.