Temporal effect of dgRTA on exposed porosity. Treatment with 10⁻⁷ mol/L dgRTA induced intercellular gaps in the HUV-EC-C monolayer that exposed pores in the support membrane. An area of ≥600 μm² per sample was examined and the number of exposed pores were determined. Data are expressed as the mean ± standard deviation. A significance level of P < .05 is indicated by an asterisk.