Antifibrotic activity of a FIEL1 small molecule inhibitor in vivo. (A) C57BL/6J mice were treated i.t. with bleomycin (0.05 U). Compounds BC-1480 and BC-1485 were given to mice at the same time through drinking water with an estimated dose of 5 mg/kg/d. Mice were euthanized over the next 1–21 d, and lungs were lavaged with saline, harvested, and then homogenized. (B–D) Lavage proteins, CXCL1, and total cell count were measured. Data represent mean values ± SEM (n = 4–8 mice per group; data are from one of two experiments performed; *, P < 0.05 compared with Vehicle, Student’s t test). (E–G) Lavage cells were also processed for Wright-Giemsa stain; Lavage macrophages, neutrophils, and lymphocytes were counted and graphed. Data represent mean values ± SEM (n = 4–8 mice per group; *, P < 0.05 compared with Vehicle, Student’s t test). (H) Survival studies of mice that were given bleomycin and BC-compound treatments. Mice were carefully monitored over time; moribund, preterminal animals were immediately euthanized and recorded as deceased. Kaplan-Meier survival curves were generated using SPSS software (n = 12–24 mice per group; *, P < 0.05 compared with Vehicle, Log-rank test P < 0.05). Vehicle, n = 24, BC-1480; n = 13, BC-1485; n = 12. (I) H&E and Trichrome staining was performed on lung samples. Bar, 100 µm. (J) Hydroxyproline content were measured in lungs from 7, 14, and 21 d after bleomycin challenge. Data represent mean values ± SEM (n = 4–8 mice per group; *, P < 0.05 compared with Vehicle, Student’s t test). (K) Collagen percentage quantification from Trichrome staining. Data represent mean values ± SEM (n = 4–8 mice per group; *, P < 0.05 compared with Vehicle, Student’s t test).