dgRTA-induced permeability. HUV-EC-C monolayers cultured on collagen IV-coated microporous cell culture inserts were either left untreated (n = 5; ○) or were exposed to 10⁻⁷ mol/L (3.0 μg/mL) dgRTA (n = 4; ♦). Monolayer permeability was measured by TEFF and is expressed as the mean ± standard deviation. Data from two separate experiments are presented here. Statistically significant differences between the mean responses of treated and time-matched control monolayers are depicted as follows: *P < .05; **P < .01.