Akt activation in lung epithelium results in RDS and lethality in preterm infants. (A) Gross appearance of infants. (B) Survival rate by 2 h after delivery. *, P < 0.05 (n = 6 control and n = 5 DTG mice from 2 dams). (C) HE staining of the lung sections of infants delivered by Caesarean section at E18.5. Scale bar, 50 μm. (D) PAS staining of the lung sections of infants delivered by Caesarean section at E18.5. Scale bar, 50 μm. (E) Saccular size at E18.5. *, P < 0.05 versus control. (F) Saccular number at E18.5. *, P < 0.05 versus control. For the experiments shown in panels E and F, n = 3 control and n = 4 DTG mice from 2 dams. (G) Western blot analysis of surfactant proteins (SP-A, SP-B, pro-SP-C, and SP-D). (H) Immunohistochemistry of HA tag (Akt1 transgene), pro-SP-C, and CC10 at E18.5. Scale bar, 50 μm. (I and J) Double immunostaining of CC10 and SP-C. CC10/SP-C double-positive cells are indicated by arrows. Scale bar, 100 μm. For both panels, n = 4 (Cont) and n = 3 (DTG) from 2 dams.