Figure 8

Immunostaining of selected marker proteins expressed in distal lung. Lung sections at E19.5 from WT control (Panels A, D, G and J), Dhcr7^-/-Tg+ (Panels B, E, H and K) and Dhcr7^-/-Tg- (Panels C, F, I and L) were immunostained with antibodies against T1-α, SP-C, caveolin-1 (cav-1), and PECAM-1, respectively. Immunostaining for SP-C shows relative similar patterns and numbers of positive cells (brown dots, indicated by arrowheads) in WT control (Panel D), Dhcr7^-/-Tg+ (Panel E) and Dhcr7^-/-Tg- (Panel F) lungs. T1-α expression in WT lung (Panel A) is confined to flattened cells lining the pre-alveolar spaces (arrow). A decreased pattern of T1-α expression, especially in undeveloped epithelial tubules (arrowheads), is clearly evident in Dhcr7^-/-Tg- lung (Panel C). Both cav-1 (Panel G) and PECAM-1 (Panel J) staining demonstrate an extensive vascular network in the well developed saccules in WT lung, however, delayed vascular development was observed in Dhcr7^-/-Tg- lung (Panel I and L). Note that T1-α, cav-1 and PECAM-1 expressive patterns in Dhcr7^-/-Tg+ lung (Panels B, H and K, respectively) appear in the middle between WT and Dhcr7^-/-Tg- lungs. Labels: a, pre-alveolar spaces; br, bronchiole.