THE EFFECTS OF BFGF ON RCS RAT EYES

Basic fibroblast growth factor (bFGF) has been implicated as a factor in retinal differentiation and disease. Recent studies have shown that subretinal or intravitreal injections of bFGF delay the retinal degen eration of the RCS rat but the global nature of this effect has been q uantified for few test animals and the mechanism underlying this effec t is not understood. In order to determine more accurately the global effects of intravitreal bFGF and to further elucidate the mechanism of bFGF promoted photoreceptor cell saving, we injected one of three bFG F doses into the vitreal cavities of young RCS rats. Using measurement s from several eyes, we confirmed that a single intravitreal bFGF inje ction globally delays the RCS dystrophy. Test eyes contained fewer deb ris zone macrophages and more inner retinal macrophages than did contr ol eyes at I month post injection. As bFGF's saving effect waned, the number of inner retinal macrophages decreased and the number of debris zone macrophages increased toward control levels. Dose-dependent cata ract formation occurred in 100% of test eyes. Eyes that received the h ighest bFGF dose showed increased retinal vascularization at 1, 2 and 3 months post injection. The possible relationships between bFGF promo ted photoreceptor survival and our findings are discussed.