Figure 6

VEGF-D expression is decreased in human IPF lung tissues. (A) Equal amounts of protein from human lung homogenates were analyzed by Western blotting with antibodies against VEGF-D and β-actin. (B) Densitometric analysis of (A). Ratio of VEGF-D to β-actin density was expressed as the fold-change relative to control lung. Data are presented as means ± SEM (n = 6). *P < 0.05, compared with control, by Student t test. (C–H) Immunoreactivity for VEGF-D visualized with diaminobenzidine (DAB) is observed in alveolar macrophages (red arrow) and epithelial cells (blue arrow) in both control (C) and IPF lungs (F). In IPF lung sections (G), fibroblastic foci (area enclosed by black dotted lines) showed very weak VEGF-D immunoreactivity, whereas VEGF-D was present within alveolar interstitial cells (black arrow) in control lungs (D). Absence of immunoreactivity with nonimmune IgG in control (E) and IPF (H) lungs. One representative image from control (n = 6) and IPF (n = 6) lungs was shown. Scale bars: 50 µm.