Effects of 4-HPA on monolayer permeability under hypertonicity and hypoxia conditions in rat lung microvascular endothelial cells (RLMVEC). RLMVEC were stimulated with HIF-1α siRNA, sFlt-1 (1 μM, vascular endothelial growth factor (VEGF)antagonist), 4-HPA, hypertonicity and hypoxia, hypertonicity and hypoxia + HIF-1α siRNA, hypertonicity and hypoxia + sFlt-1, hypertonicity and hypoxia + 4-HPA for 4 h, respectively. The RLMVEC monolayer permeability was measured with FITC-albumin (50 μM). Data are means ± SD, *
p < 0.01 vs. control group, #
p < 0.05 vs. hypertonicity and hypoxia group.