Fig 6. Hyperoxia-induced inhibition of RAR expression in vitro.

A549 cells were plated in 100-mm dishes at a density of 5x10⁵cells/mL. The cells were then cultured in a humidified chamber under normoxic (95% air-5% CO₂) or hyperoxic (95% oxygen- 5% CO₂) conditions for 2 or 3 d. The cells were then harvested and assayed for RARα and RARγ expression. The expression levels were normalized to a GAPDH internal control. *P<0.05, vs. normoxic group, all statistical comparisons by one-way ANOVA with Fisher's LSD as post-hoc procedure.