Regenerated lung constructs attached to an in vitro lung bioreactor (pa, pulmonary arterial cannula; pv, pulmonary venous cannula; tr, trachea) during inspiration (right; RUL, right upper lobe; RML, right middle lobe) and expiration (left). (Reprinted with permission from ref182. Copyright 2010 Nature Medicine). (A) A three-dimensional micro-CT rendering of the acellular matrix airway compartment, with large airways shown in green, compared with (B) angiography of the vascular compartment (red) (4 mm scale bar). (C) Smaller vessels are visualized with micro-CT (500 μm scale bar). (D) Immunoblot for MHC-1, MHC-II, and β-actin demonstrate removal of cellular proteins during decellularization. Next, they compared Hematoxylin and eosin (H&E) stained native rat lung (E) and decellularized lung matrix. (F) (50 μm scale bar). (G) Quantification of Collagen, elastin, glycosaminoglycan, and DNA contents of the native lung (black bars) compared to the acellular lung ECM matrix (hatched bars). (Reprinted with permission from ref183. Copyright 2013 Science).