The effects of sodium orthovanadate–induced phosphatase inhibition on rat retinal pigment epithelium cell activity

Abstract

Purpose: The purpose of this study was to assess the contribution of sodium orthovanadate (SOV)-induced phosphatase inhibition to the activation of rat retinal pigment epithelium (RPE) cells.Methods: Confluent cultures of rat RPE cells were treated with the general phosphatase inhibitor SOV. The effects of SOV on the cell cycle were determined by flow cytometry and protein detection of cyclin A and cyclin D1, two different cell cycle regulatory factors. The effects of SOV on cell differentiation were confirmed by immunostaining for α-smooth muscle actin (α-SMA). A migration assay was used to evaluate the effects of SOV on cell migration.Results: SOV could accelerate the cell cycle of RPE cells. Western blotting showed that SOV significantly increased the expression of cyclin A and cyclin D1 in a dose-dependent fashion. The results of α-SMA staining and western blotting demonstrated that SOV induced RPE cells to differentiate toward better contractility and motility. The migration assay indicated that SOV improved the migration activity of RPE cells.Conclusions: Sodium orthovanadate can improve proliferation, differentiation, and migration of rat RPE cells and can also induce the reentry of contact-inhibited rat RPE cells into the cell cycle.