Alveolar capillary bed formation is impaired by Akt1 overexpression in lung epithelium, which is improved by rapamycin administration to the dams. (A) Histological analysis of vehicle- or rapamycin-treated pups at P0. Sections were stained with isolectin B4-FITC conjugate (green) to detect endothelial cells and with wheat germ agglutinin-TRITC conjugate (red) for membrane staining. Scale bar, 50 μm. (B) Alveolar capillary density. *, P < 0.05 versus vehicle-treated control mice; †, P < 0.05 versus vehicle-treated DTG mice. In the vehicle-treated group, n = 4 control and n = 3 DTG mice from 2 dams; in the rapamycin group, n = 4 control and n = 4 DTG mice from 2 dams. (C) Histological analysis of vehicle- or rapamycin-treated wild-type pups born by Caesarean section at E17.5. Scale bar, 50 μm. (D) Alveolar capillary density. *, P < 0.05 versus vehicle-treated mice (n = 4 vehicle-treated mice from a single dam, and n = 4 rapamycin-treated mice from 2 dams).