(A) Six-week-old WT and ApoE–/– male mice were i.t. instilled with saline or bleomycin (BLM, 1.5 U/kg in 50 μL saline). Three weeks after treatment, mice were sacrificed for AM isolation and fibrosis evaluation. (B) Total RNA of the lungs and AMs from the experiment in A were purified and real-time PCR performed to assess the expression of ApoE. n = 3 mice for each group. (C) The levels of hydroxyproline in the lungs were determined. n = 3, 7, 3, 6 mice for WT Saline, WT BLM, ApoE–/– Saline, and ApoE–/– BLM, respectively; mean ± SEM; **P < 0.01 by 1-way ANOVA with Bonferroni’s post hoc test. (D–E) Representative images of H&E staining (D) and Masson’s trichrome staining for collagens (E) of the lungs from this experiment are shown. Original magnification, ×40 (D), and ×200 (E). Scale bars: 500 μm (D) and 100 μm (E).