FIG. 2.

Decellularized macaque lungs retain the ultrastructural and microanatomical features of native lungs. (A) H&E stain demonstrates a similar histological appearance of bronchioles (B), respiratory bronchioles (RB), blood vessels (BV), alveolar sacs (AS), and capillaries (C) in both native and decellularized lung. (B–I) Native and decellularized macaque lungs were stained with H&E (B, F), Gomori's trichrome (C, G), and modified Movat's pentachrome (D, H), to examine various histological features. Efficiency of decellularization is evident from the lack of darkly staining nuclei in H&E, Gomori, and Movat's stains. Gomori shows that preserved collagen (green) remains in abundance after decellularization. Movat's stain shows the presence of septal elastic tissue (gray arrows) and axial elastic tissue (black arrows) in both native and decellularized lung; there is visibly less elastic tissue in the decellularized lung as noticed by this stain. (E, I) Alcian blue stain was used to observe the content of GAG in native and decellularized lungs. GAG are preserved through decellularization but take on a ragged appearance histologically. (J) Native and decellularized lung have similar parenchyma-to-airspace area, but (K) acellular lung has a slightly but significantly lower MLI than native lung (p<0.0001), suggesting that decellularization produces alveoli that are of slightly larger diameter than native lungs. Insets represent a 2× enlarged portion of each field to show fine details. The asterisk indicates p<0.05 by Student's t–test. H&E, hematoxylin and eosin; MLI, mean linear intercept; GAG, glycosaminoglycans. Color images available online at www.liebertpub.com/tea