Reduction of lung stretch-induced collagen gene expression and epithelial-mesenchymal transition in Akt-deficient mice.
After five days of bleomycin treatment, real-time polymerase chain reaction of fibronectin (A), MMP-9 (B), and 1a1 (C) mRNA expression were from the lungs of nonventilated control mice and mice ventilated at a tidal volume of 30 mL/kg for 5 h with room air (n = 5 per group). Arbitrary units were expressed as the ratio of fibronectin, MMP-9, and 1a1 mRNA to GAPDH (n = 5 per group). Representative photomicrographs (x400) with E-cad (red), α-SMA (red), and Hoechst (blue) immunofluorescent staining of paraffin lung sections (D) (n = 5 per group), and micro-computed tomography imaging (E) (n = 3 per group) five days after administering bleomycin were from nonventilated control mice and mice ventilated at a tidal volume of 30 mL/kg for 5 h with room air. Positive red staining in the fibroblasts is identified by arrows (n = 5 per group). The fibrotic scoring (F) was quantified as the average number of 10 nonoverlapping fields in Masson’s trichrome staining of paraffin lung sections (n = 5 per group). Scale bars represent 20 μm. ANOVA was used to assess the statistical significance of the differences, followed by multiple comparisons with a Scheffeˊs test, and a P value < 0.05 was considered statistically significant. * P< 0.05 versus the nonventilated control mice with bleomycin pretreatment; †P< 0.05 versus Akt+/- group.