Fig. 2.

Lung fibrosis is associated with an increased number of monocyte-derived alveolar macrophages in old mice. Young adult mice (3 to 5 mo) and old mice (18 to 24 mo) were administered bleomycin (0.025 unit/50 μL, intratracheally) or crocidolite asbestos (100 μg/50 μL, intratracheally), and the lungs were harvested 28 d later. Monocyte and macrophage populations in (A) bleomycin-induced lung fibrosis (Bleo) and (B) asbestos-induced lung fibrosis were quantified via flow cytometry. Data presented as mean ± SEM, number of mice shown on the plot, one-way ANOVA with Tukey test for multiple comparisons. *P < 0.05. Representative data from two independent experiments.