Glucocorticoids Enhance the Expression of Sodium Bicarbonate Co–Transporter (NBC) in Cultured Human Corneal Endothelial Cells

Abstract

Abstract: : Purpose: Glucocorticoids are widely utilized in ophthalmic therapies because of their strong anti–inflammatory effects. Although it is known that glucocorticoids also reduce non–inflammatory corneal edema in the clinical setting, its mechanism has not been identified yet. The purpose of this study was to examine the effect of glucocorticoid on the expression and activity of sodium bicarbonate co–transporter (NBC), which is known as important component of water transportation in corneal endothelium. Methods: Cultured human corneal endothelial cells (HCECs) were used. We applied 10^–7M dexamethasone on HCECs for several days, and then examined the NBC–mRNA and protein expression levels by semi–quantitative RT–PCR and western blotting, respectively. Functional activities of NBC are evaluated by measuring intracellular pH(pHi) by fluorophotometry. Results: The expression levels of both NBC–mRNA and NBC–protein in HCECs were elevated by the administration of dexamethasone. The functional activities of NBC in HCECs were increased as evidenced by measurement pHi. Conclusions:Glucocorticoids enhances the NBC activities in cultured HCECs.

Keywords: cornea: endothelium • corticosteroids