Fig. 2
NO-GC expression distinguishes two types of myofibroblasts in fibrotic lung. Bleomycin was used to induce lung injury in WT mice. Lungs were isolated 21 days after bleomycin treatment. Lung tissue was stained with antibodies against NO-GCβ1, αSMA, col1α1, laminin 1 and PDGFRβ. A Overview of bleomycin-treated lung in which fibrotic areas can be discerned from non-fibrotic areas by parenchymal/extravascular αSMA expression (circled areas). B NO-GC expression distinguishes two types of αSMA + myofibroblasts (NO-GC+, yellow; arrowheads or NO-GC−, green; asterisks). Myofibroblasts are only found in the fibrotic area marked by the dotted lines in b2/b3. See Additional file 1: Fig. S2 for enlargement. C, D αSMA+ myofibroblasts (green) in the former lumen of alveoli defined by col1α1 signals (red) as marker of the alveolar wall or laminin 1 as marker of the basement membrane. Interstitial myofibroblasts are indicated by arrowheads. E PDGFRβ (green) co-localizes with NO-GC in pericytes and myofibroblasts in the alveolar wall (yellow). Intra-alveolar PDGFRβ+ myofibroblasts (asterisks in d1) do not stain for NO-GC. DAPI was used to stain nuclei (blue). Single channels are shown in a2–e2 and a3–e3