Endothelial cells exposed to cycling hypoxia display a proinflammatory phenotype that is characterized by IL-8 and ICAM-1 mRNA overexpression. EAhy926 cells and HUVEC were exposed to N, chH, or cyH with or without TNFα (0.1 ng/ml) for 6 hours. The relative abundance of IL-8 (A), ICAM-1 (B), and IL-6 (C) mRNA was evaluated directly after the incubation (6h+0hR) by RT-qPCR (n= 3, mean ± 1 SD). Statistical analysis was performed by two-way ANOVA and Holm-Sidak test as post hoc test. * chH/cyH versus corresponding N, $ cyH versus corresponding chH, # TNFα versus corresponding control. *, $, #, P < .05; **, $$, ##, P < .01; ***, $$$, ###, P < .001.