FGF receptor 1 expression in experimental choroidal neovascularization.

Fibroblast growth factor (FGF) is an important factor in neovascularization. To clarify the role of FGF, we demonstrated the expression of FGF receptor 1 mRNA in experimentally induced choroidal neovascularization using in situ hybridization. Krypton laser photocoagulation was applied to the posterior retina of colored rats to induce choroidal neovascularization; the eyes were removed at various intervals after photocoagulation. Chorioretinal sections were made, and FGF receptor 1 cDNA fragments were used to make antisense and sense probes for in situ hybridization. In normal chorioretinal tissue, stain indicating FGF receptor 1 mRNA was observed in the ganglion cells and the inner nuclear layer. After photocoagulation, FGF receptor 1 mRNA appeared in the retinal pigment epithelial cells, in melanocytes of the choroid and in the choroidal blood vessel wall of the photocoagulation lesions. This suggests that FGF is involved in the process of neovascularization. Previous studies have reported that the capillary endothelial cells and retinal pigment epithelial cells produce basic FGF in vitro; FGF may affect the cells in an autocrine or paracrine manner.