The Effect of Brimonidine on Transepithelial Resistance in a Human Retinal Pigment Epithelial Cell Line

Purpose: To investigate the effects of brimonidine, an α-2-adrenergic agonist, on barrier function in ARPE-19 cells by measuring transepithelial resistance (TER). Methods: ARPE-19 cells were cultured into a confluent monolayer on a microporous filter. Brimonidine was added to the apical medium, and the barrier function of the cells was evaluated by measuring TER. A subset of cells was treated under hypoxic conditions, and the TER changes observed upon administration of brimonidine were compared to those observed in cells in normoxic conditions. Results: The ARPE cell membrane reached a peak resistance of 29.1±7.97 Ωcm2 after four weeks of culture. The TER of the cells treated under normoxic conditions increased with brimonidine treatment; however, the TER of the cells treated under hypoxic conditions did not change following the administration of brimonidine. Conclusions: Barrier function in ARPE-19 cells increased with brimonidine treatment. Understanding the exact mechanism of this barrier function change requires further investigation.