Figure 8. Myeloid ablation of Malat1 promotes bleomycin-induced pulmonary fibrosis.

(A) Malat1^fl/fl and Malat1 mye^–/– mice were i.t. instilled with 50 μl saline or 1.5 U/kg bleomycin (BLM) in 50 μl saline. Three weeks after bleomycin administration, mice were sacrificed and lung homogenates prepared. Levels of hydroxyproline in the whole lungs were determined. n = 3, 9, 4, 10 mice for each group; mean ± SE. (B) The experiments were performed as in A. Lungs were fixed with 10% formalin and sections prepared. Masson’s trichrome staining was performed. Original magnification, ×20. Scale bars: 100 μm. (C and D) The experiments were performed as in A. BAL cells were collected and resident and recruited macrophages sorted. Total alveolar macrophage numbers (C) and relative numbers of resident and recruited macrophages (D) were determined. n = 3, 3, 3 mice for each group; mean ± SE. (E–H) The experiments were performed as in A. BALFs were prepared and alveolar macrophages in the BALFs harvested. Levels of the indicated genes in the cells were determined by real-time PCR. ● Malat1^fl/fl BLM, ▲ Malat1 mye^–/– BLM; n = 9 mice for each group; mean ± SE. *P < 0.05; **P < 0.01; ***P < 0.001 by 1-way ANOVA with Bonferroni’s post hoc test (A, C–H).