Figure 2.

Effects of apical hyperosmolarity on trans-epithelial electrical resistance, cell morphology and epithelial permeability to macromolecules markers. Differentiated Caco-2 cells cultured on Tranwell filters for 15 days were treated during 2- or 24-h with hyperosmotic or control isosmotic media applied at the cellular apical side. (A) TER was measured before the hyperosmotic stress (t₀) and after 2- or 24-h treatment. (B) Light microscope images of cell monolayers were acquired in the different experimental conditions using a 20x objective and the default exposition parameters. (C) Paracellular and (D) transcellular permeabilities were estimated by measuring the FD4 and HRP content respectively in the basal side medium at the end of the experiments. Values are from three independent experiments (n = 4–9 for each experimental group). Mean significant differences (P < 0.05) are indicated by a different letter. Main factor and interaction effects are indicated with *P < 0.05, **P < 0.01 and ***P < 0.001. NS: Non-significant difference.