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

Abstract

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.

Keywords

ciliary pigment epithelium / transforming growth factor-beta1 / dexamethasone

References

[1] Flugel-KochC, OhlmannA, PiatigorskyJ, et al.. Disruption of anterior segment development by TGF-beta1 over-expression in the eyes of transgenic mice. Dev Dyn, 2002, 225: 111-125

[2] XiongX C, DuS H, ZhangL. Culture of human and rabbit ciliary pigment epithelial cells technique and morphological study. Ophthalmol (Chinese), 1994, 3: 114-117

[3] XiongX C, DuS H, WeiH R, et al.. Choice of medium for ciliary pigment epithelial culture and observation of its ultrastructural characteristics. Rec Adv Ophthalmol (Chinese), 1999, 19: 162-164

[4] XuG X, HuJ Z, ZhengW D, et al.. Expression and significance of transforming growth factor-β1, matrix metalloproteinase-2 and its inhibitor in lens epithelial cells of diabetic cataract. Chin J Ophthalmol (Chinese), 2003, 39: 411-414

[5] Schlotzer-SchrehardtU, DorflerS. Immunolocalization of growth factors in the human ciliary body epithelium. Curr Eye Res, 1993, 12: 893-905

[6] ObataH, KaburakiT, KatoM, et al.. Expression of TGF-beta type I and type II receptors in rat eyes. Curr Eye Res, 1996, 15: 335-340

[7] ObataH, KajiY, YamadaH, et al.. Expression of transforming growth factor-beta superfamily receptors in rat eyes. Acta Ophthalmol Scand, 1999, 77: 151-156

[8] YoshidaM, TakeuchiM, StreileinJ W. Participation of pigment epithelium of iris and ciliary body in ocular immune privilege. 1. Inhibition of T-cell activationin vitro by direct cell-to-cell contact. Invest Ophthalmol Vis Sci, 2000, 41: 811-821

[9] XiongX C. The advance in the study of ciliary body epithelia and the secretion of aqueous humor. Section Ophthalmol Foreign Med Sci (Chinese), 1994, 18: 205-208