Fig. 4.

Genetic deletion (KO) of phospholipase D1/2 genes Pld1 and Pld2 (Pld1^−/− and Pld2^−/−) reduces bleomycin-induced apoptosis in mouse lung. Wild-type (WT), Pld1^−/−, and Pld2^−/− mice were challenged intratracheally with bleomycin (1.5 U/kg in 50 μl PBS) or sterile PBS and euthanized on day 7 post-bleomycin administration as described in Fig. 2. A: representative photomicrographs of TUNEL-positive staining of lung tissue sections. Apoptotic nuclei are stained brown and marked by arrows. B: number of TUNEL-positive cells per field in lung sections. *P < 0.05, **P < 0.005. C: higher magnification, at ×40, indicates that TUNEL-positive cells are mostly epithelial. D: representative Western blot showing protein expression of fibrotic marker fibronectin (FN) in lung tissue as described in Fig. 3 with and without bleomycin (Bleo;) challenge on day 21. E and F: representative Western blot showing PLD1 and PLD2 expression, respectively, in lung tissue lysates from WT, Pld1^−/−, and Pld2^−/− mice.