Protective effect of quercetin on hydrogen peroxide-induced tight junction disruption.

Tight junction is a crucial structure in the control of paracellular transport across epithelial/endothelial barriers. This study investigated the protective effect of quercetin against hydrogen peroxide (H(2)O(2))-induced tight junction disruption and hyperpermeability in ECV304 monolayers. Nonlethal concentration of H(2)O(2) (100 micromol/L; 4 hours) decreased expression of the tight junction proteins zonular occudens (ZO)-1 and occludin as well as disrupted the junction structure at the cell border.