Abstract
Present work investigates the potential of absorption enhancers (glucose, EDTA, sodium cholate, SDS, ethanol and menthol) to open the cellular tight junctions and in doing so improve the paracellular permeability of macromolecules. Initial work assessed cytotoxicity (through MTT assays) of absorption enhancers on Caco-2 cells to confirm the suitable concentration and action time. Subsequently, macromolecular permeability across filter-cultured Caco-2 monolayers was detected. The six enhancers were also tested for the effect on the distribution of the tight junction proteins, ZO-1, claudin-1, occludin, and E-cadherin. The results showed that the six enhancers at certain concentration and action time caused little cytotoxicity to Caco-2 cells and increased the permeability of fluorescein isothiocyanate (FITC) and FITC-dextrans, as well as producing changes in ZO-1, claudin-1, occludin, and E-cadherin distribution, indicating a tight junction effect.