Figure 2.

Submersion and hypoxia induce hypoxia-inducible factor (HIF) 1α and HIF-2α proteins. NHBE cells cultured 72 hours at an air–liquid interface (ALI) in air (21% O₂) then switched to an ALI in hypoxia (0.5%; Hyp.) or submerged (0.5 ml; Sub.) for 5 hours. (A) Western blots of whole-cell protein lysates with antibodies to HIF-1α, HIF-2α, and β-actin showing both HIF-1α and HIF-2α induction in submerged and hypoxic conditions compared with ALI (Air) control. (B) Densitometry quantification of the Western blot data from two lungs. The data show increases in HIF proteins, indicating that submersion causes a hypoxic environment. β-actin was used as a loading control. Data shown are means (± SEM).