Figure 8

Immunostaining patterns for caveolin-1α and PECAM-1 in lung sections. Cav-1α staining was compared at E14.5, E17.5 and E20.5 stages of development. Both the epithelium and mesenchyme were negative for cav-1α at E14.5. Developing blood vessels (red arrowheads) and capillaries (arrows) (panels A and B) were stained positively for cav-1α, but the staining patterns between wild-type (+/+) and knockout (-/-) lungs were not altered. Cav-1α was also detected at the proximal bronchiole sub-epithelial matrices (panels A-D, black arrowheads). At E17.5, the airway epithelium, negative for cav-1α staining, was surrounded by rings of cav-1α positively stained capillary networks (panels C and D, arrows). Cav-1α expression patterns in lungs from knockout embryos at E17.5 were similar to wild-type embryos, but relative less capillary bed was noted in knockout lungs (cf. panels C and D). At E20.5 of wild-type lungs, both cav-1α and PECAM-1 staining demonstrated an extensive vascular network in the well developed saccules, with staining observed in close proximity to flat epithelial cells lining the air spaces (panels E and G, arrows). However, delayed vascular development was observed in knockout lungs, showing capillaries (panels F and H, arrows) of the knockout lungs at E20.5 were embedded in a relatively thick mesenchyme around the undeveloped epithelial tubules in which the epithelial cells were remained cuboidal (arrowheads). Original magnification: A-D are 20X; E-H are 40X.