Rosiglitazone modifies PEDF gene expression and protein levels in the Koletsky rat choroid-RPE complex

The purpose of this study was to determine whether rosiglitazone, a peroxisome proliferator-activated receptor (PPAR)γ ligand, altered growth factor expression in the choroid-RPE complex of Koletsky rats. Using lean and obese Koletsky rats fed a normal or rosiglitazone-supplemented diet, gene and protein expression of vascular endothelial growth factor (VEGF), pigment epithelial derived growth factor (PEDF), angiopoietin 1, and its receptor, Tie-2, were assessed. Both gene expression and protein expression of PEDF were significantly increased in both obese and lean Koletsky rats treated with rosiglitazone diet. Gene expression of VEGF, angiopoietin-1 and Tie-2 were increased after rosiglitazone treatment, without changes in protein expression. Since PPARγ ligands have been implicated in vascular remodeling, these results suggest that upregulation of PEDF expression may be a potential mechanism in the rat choroid-RPE complex.