Figure 7

Lung histology in wild-type, knockout and knockout-transgenic embryos. Histological sections of lungs from WT, Dhcr7^-/-Tg+ and Dhcr7^-/-Tg- at term (E19.5) were stained with hematoxylin/eosin (H & E) and photographed. WT lung depicts late saccular phase of lung development (Panels A and B). Considerable elongation of the secondary crests (arrows) and a more thinned mesenchyme are evident throughout the WT lung. Dhcr7^-/-Tg- lung showed less distal saccular structures, had thick-walled mesenchyme and septation appeared not to be progressing, with undeveloped epithelial tubular structures (arrowheads) throughout the lung fields (Panels E and F). Although these changes are also present in the lungs from transgenic-KO lungs, less severe hypoplasic lung phenotypes are evident in Tg+ mutant mice (Panels C and D, arrows show secondary crests), compared to WT and Dhcr7^-/-Tg- animals. Panel G shows the morphometric analyses of lung terminal sac spaces in lungs of WT, Dhcr7^-/-Tg+ and Dhcr7^-/-Tg- at E19.5. Results are expressed as mean ± SD. Labels: a, pre-alveolar spaces; br, bronchiole.