Figure 2.

Deletion of Sphk1 in alveolar epithelial cells protects mice against bleomycin-induced lung fibrosis. Sphk1^flox/flox and Sphk1^flox/flox: SPC-Cre⁺ mice (male, 8 weeks; n = 4–6 per group) in C57BL/6 background receiving bleomycin (BLM) (2 U/kg in 50 µL PBS) or PBS intratracheally were sacrificed at day 21 post-challenge. (A) Illustrative H&E images of lung sections obtained from Sphk1^flox/flox and SPC-Sphk1KO mice with/without BLM challenge. Original magnification, ×10; Scale bar: 200 µm. (B) Total cell number in bronchoalveolar lavage (BAL), and (C) total protein levels in BAL. (D) Masson’s trichrome staining for collagen deposition. Representative images of Masson’s trichrome staining of lung sections obtained from Sphk1^flox/flox and SPC-Sphk1KO mice with/without BLM challenge (blue arrows showing blue of collagen deposition area). (E) Acid soluble collagen levels in lung tissue. (F) Expression of fibronectin (FN), and α-smooth muscle actin (α-SMA) in mice lung tissue from Sphk1^flox/flox and Sphk1^flox/flox: SPC-Cre⁺ mice stimulated with BLM having glyceraldehyde 3-phosphate dehydrogenase (GAPDH) as loading control. * p < 0.05 vs. control.