Background: Flavonol quercetin has beneficial effects for promoting epithelial barrier function in intestinal and airway epithelium; however, information is limited regarding its effects on the endometrium.

Objective: We investigated the potential effect of quercetin on epithelial barrier function and its protective effect on lipopolysaccharide (LPS)-induced disruption of barrier function in endometrial epithelial cells.

Material and Method: Immortalized porcine endometrial epithelial cells grown on porous membrane filters were treated with different concentrations of quercetin or LPS for 24 to 48 h. In experiments with LPS stimulation, the cells were treated with quercetin for 24 h prior to addition of LPS and further incubation for 24 h. The endometrial barrier function was assessed by measuring transepithelial electrical resistance (TER) and paracellular fluorescein isothiocyanate-dextran (FD-4) flux.

Results: Quercetin (1, 10 and 100 μM) concentration-dependently increased TER within the first hour reflecting increased membrane integrity, whereas high concentration (200 μM) significantly decreased TER at the first hour and persisted up to 48 h. However, the paracellular FD-4 transport was decreased by 1 and 100 μM quercetin. LPS exposure significantly disrupted endometrial barrier function as evidenced by decreased TER and increased FD-4 fluxes. This LPS-mediated barrier disruption was significantly reversed by pretreatment with quercetin at 1 and 10 μM.

Conclusion: Quercetin at concentrations less than 100 μM has a potential role in preserving endometrial epithelial barrier function. The reversibility effect of quercetin on endometrial barrier disruption induced by bacterial endotoxin could be considered of using quercetin to protect endometrial barrier against bacterial infection.

Keywords: Endometrial epithelium, Lipopolysaccharide, Tight junction, Transepithelial electrical resistance, Paracellular permeability