Inhibitory effect of dexamethasone on TGF-β1 expression of rabbit ciliary pigment epithelia culturedin Vitro

Summary

In order to elucidate the effect of dexamethasone on the expression of transforming growth factor-betal (TGF-β1) in ciliary pigment epithelial (CPE) cells cultured in vitro, rabbit CPE cells were cultured in vitro, treated with DMEM medium containing 0,1×10⁻⁸, 5×10⁻⁸, 10×10⁻⁸ and 50×10⁻⁸ mol/L dexamethasone respectively for 5 days. The TGF-β1 expression was detected by immunohistochemistry Supervision methods and analyzed semi-quantitatively by HMIAS-2000 image system. As opposed toin vivo, rabbit CPE cells expressed TGF-β1 under cultured circumstance in vitro. The gray scales of the positive yellow staining in the groups of 1×10⁻⁸, 5×10⁻⁸, 10×10⁻⁸ and 50×10⁻⁸ mol/L dexamethasone were 136.57±4.43, 140.20±6.10, 142.98±2.99, 146.80±1.68 and 150.05±1.94 respectively. When the concentrations of dexamethasone were equal to or higher than 5×10⁻⁸ mol/L and, the expression of TGF-β1 was inhibited. 10⁻⁷ mol/L dexamethasone showed a significant inhibition. It was suggested that CPE cells possess the potential ability of synthesizing and expressing TGF-β1. The inhibition of TGF-β1 expression by dexamethasone may be beneficial to the treatment of proliferative vitroretinopathy, also exert some influence on the secretion of aqueous humor and ciliary inflammation.