Fig. 4.

α₃-integrin Western blots and immunohistochemistry. A: representative α₃-integrin Western blot and summary densitometry showed similar levels of α₃-integrin in BPS and CCAM tissue compared with alveolar stage lung tissue. CCAM tissue, however, had significantly increased α₃-integrin protein levels compared with canalicular period lung tissue samples (*P = 0.03, CCAM vs. Can, means ± SE; n = 6, Can; n = 3, Alv; n = 4, BPS; n = 7, CCAM). B: human fetal lung tissue (17-wk human gestation) showed α₃-integrin purple VIP staining at basal surface of columnar epithelial cells that had less intense subepithelial brown nuclear staining for Hoxb5 protein in mesenchymal cells (arrowhead). In contrast, airways (*) with less intense purple epithelial α₂-integrin staining had more intense brown Hoxb5 staining in adjacent subepithelial fibroblasts (arrow). α₃-integrin (purple) was also seen diffusely in mesenchyme but to a lesser degree than in airway epithelial cells and subepithelial fibroblasts. C: CCAM tissue had diffuse purple staining for α₃-integrin (arrowhead) and scattered brown nuclear staining for Hoxb5 protein (arrow). D: immunostaining control showed that in absence of Hoxb5 primary antibody, no brown DAB staining was seen with only purple VIP staining for α₃-integrin in presence of α₃-integrin primary antibody.