FIG. 3.

12-LOX deficiency reduces lung fibrosis after thoracic irradiation. Wild-type mice (WT) or 12-LOX-deficient mice (Alox12^−/−) were subjected to 5 × 6 Gy thoracic irradiation and followed until tissue collection at 16 weeks postirradiation (n = 5). Panel A: Lung sections collected at 16 weeks postirradiation were subjected to Masson’s trichrome staining (collagen: light blue; epithelia: red; nuclei: dark blue). Dense fibrotic foci are evident in irradiated (5 × 6 Gy) wild-type mice but are markedly reduced in the lungs of similarly treated Alox12^–/– mice. Panel B: The number of fibrotic foci per lung was assessed using Masson’s trichrome stained specimens. Panels C and D: Hydroxyproline content and percentage of AECII with senescence-associated β-galactosidase activity, respectively were assessed in lung tissue. Lung sections from the 16-week timepoint were immunostained for (panel E) CD68 and (panel F) arginase-1, and counterstained with hematoxylin (blue). Representative high-power images are presented. Columns are the mean and bars represent SD, *P < 0.05 to isogenic untreated control by ANOVA with Tukey’s correction. **P < 0.05 for comparison to radiated wild-type by ANOVA with Tukey’s correction.