FIGURE 1.

Comparative histology (A–J) and macroscopic analysis (K, L) of postnatal wild-type and Hoxa5^−/− lungs. At P0, mutant lungs were collapsed in contrast to wild-type specimens (A, B). Alveogenesis initiated normally at P5 in control samples (C, arrowheads), whereas in Hoxa5^−/− lungs, the parenchyma was thickened and few septa were noticed (D). At P15, alveoli were readily observed in controls (E, arrows), but Hoxa5^−/− lungs rather displayed enlarged airspaces (F, asterisk). At P31 (G, H, K, L) and P60 (I, J), Hoxa5^−/− lungs presented an emphysema-like phenotype (H, J, L) with areas depleted of alveoli (open arrow and asterisk) or large tubular structures (open arrowhead), whereas other regions were atelectatic (inset in H) when compared with the normal lung architecture (G, I, K). Scale bars = 100 μm.