Resveratrol and Large-Conductance Calcium-Activated Potassium Channels in the Protection of Human Retinal Pigment Epithelial Cells

Abstract

This study was undertaken to examine the possible association of large-conductance calcium-activated potassium channels (BK_Ca channels) and human retinal pigment epithelial (RPE) R-50 cell phagocytosis. The potential antioxidative effect of resveratrol in human RPE cells also was investigated.

Cultured human RPE R-50cells were treated with hydrogen peroxide ( H₂O₂, 10 μM, 20 min), meclofenamic acid (30 μM, 20 min), paxilline (100 nM, 20 min), or resveratrol (10 μM, 20 min), respectively. Meclofenamic acid (30 μM, 20 min) or resveratrol (10 μM, 20 min) was given after exposure to H₂O₂ . Pretreatment with meclofenamic acid, resveratrol, or paxilline before H₂O₂ exposure also was performed. Fluorescent latex beads then were fed for 4 h, and phagocytic function was assessed by flow cytometry.

H₂O₂ inhibited the phagocytic function of human RPE R-50 cells. The BK_Ca channel inhibitor, paxilline, inhibited RPE phagocytosis, as did hyperoxide stress. The BK_Ca channel opener, meclofenamic acid, prevented the damage caused by H₂O₂ . Pretreatment with resveratrol also provided protection against damage caused by H₂O₂ . However, further treatment with resveratrol or meclofenamic acid was not found to offer protection from H₂O₂ exposure.

In conclusion, the dietary antioxidant, resveratrol, significantly reduced oxidative damage on phagocytic function in human RPE R-50 cells. One of the underlying mechanisms might be linked to the activity of BK_Ca channels in RPE cells.