Representative histological features of healthy and septic human lungs and immunohistochemical staining for WNT5A and MMP7 activation in normal and septic human lungs. (A-D) Histological features: (A) normal lung (healthy) and (B) septic lung showing pulmonary infiltrates and perivascular edema; (C) normal lung and septic lung (D) stained with Sirius-red assay for collagen content (× 200 magnification). (E- H) WNT5A (E, F) and metallopeptidase (MMP)7 (G, H) are shown in red-pink color. Tissues were counterstained with hematoxylin. There was increased immunoreactivity for WNT5A and MMP7 in alveolar walls and septa (× 200 magnification).