Fig. 4

Anti-fibrotic and inflammatory effects of vascular endothelium–specific GC-A overexpressed mice in BLM-induced pulmonary fibrosis. BLM was administered intratracheally into vascular endothelium–specific GC-A overexpressed (Tg) mice and WT littermates on Day 0, and lung tissues were removed on Day 21. Representative micrographs of lung tissue stained with hematoxylin–eosin (HE: upper panels) and Masson trichrome (MT: lower panels): WT littermates treated without BLM (a, e), vascular endothelium–specific GC-A overexpressed mice treated without BLM (b, f), WT littermates treated with BLM (c, g), and vascular endothelium–specific GC-A overexpressed mice treated with BLM (d, h) are shown. Scale bar: 500 μm. i Fibrotic area was measured using image analysis software and is expressed as a percentage of the whole lung field. Values represent means ± SEM (WT without BLM, n = 4; Tg without BLM, n = 3; WT with BLM, n = 5; Tg with BLM, n = 5). *p < 0.05. NA, not assessed because of the absence of fibrotic area in normal lungs. j–m Numbers of total cells (j), macrophages (k), neutrophils (l), and lymphocytes (m) in bronchoalveolar lavage (BAL) fluid on Day 21 after BLM administration. Values represent means ± SEM (n = 5 mice per group). *p < 0.05. Lung sections obtained 21 days after BLM administration were stained with Mac-3 in WT littermates treated without BLM (n), vascular endothelium–specific GC-A overexpressed mice treated without BLM (o), WT littermates treated with BLM (p), and vascular endothelium-specific GC-A overexpressed mice treated with BLM (q). Representative images are shown at 200× magnification. Macrophages were identified by Mac-3 staining. r Mac-3–positive cells were counted in ten high-power fields (HPF), and the data are expressed as means ± SE. (n = 3–5 mice per group). *p < 0.05