2.10. FITC-Dextran Epithelial Permeability Assay

Permeability was assessed by measuring the flux of FITC-dextran from the upper compartment to the lower compartment in Transwell plates (pore size 0.4 μm; polyester membrane, Corning, New York, USA). Caco-2 cells were grown until full confluency in 12 well Transwell plates. Here, we applied the same treatment groups as described in the impedance-based technique. Cells were treated with 1000 μM H₂O₂ or pretreated with 10 μM olaparib for 30 minutes. After 24 hours, FITC-dextran solution (1 mg/ml) was added to the upper chamber. 1 hour later, a medium from the lower chamber was collected and the fluorescence intensities were detected by a Promega GloMax plate reader (Promega, USA) at 490- nm excitation and 510–570 nm emission wavelengths.