Fig. 5

Effect of CA on epithelial barrier integrity after exposure to UPM. a Transmembrane epithelial resistance (TEER) was measured using a voltohmmeter. Cells were cultured under non-treated, only CA, only UPM, and CA + UPM treated conditions for 0–15 days. CA (10 μM) was applied on day 8 for 24 h, and UPM (100 μg/mL) on day 9 for 6 h. Asterisks denote significant difference compared to each day control, p < 0.001, two-way ANOVA. b Paracellular permeability assay was performed using cells cultured with FITC-dextran 4000 Da (final concentration, 0.17 mg/mL). An empty filter was used as the negative control. After pretreatment with 10 μM CA for 24 h, and NCI-H441 cells were incubated with UPM (100 μg/mL) for 6 h. Data are means ± SD of three experiments with triplicate samples and different letters indicate significant differences at p < 0.05 by Tukey’s multiple comparisons test