Effects of basic fibroblast growth factor in retinal ischemia

Purpose. Basic fibroblast growth factor (bFGF), a 17- to 24-kDa protein known to be essential for the survival of neurons, induced fiber outgrowth of ganglion cells in cultures of rat retina and rescued photoreceptor cell loss in the retina of Royal College of Surgeon rats. The authors evaluated the efficacy of bFGF in rescuing the neuronal loss in rat retina after retinal ischemia. Methods. Retinal ischemia was induced in 29 eyes of 17 albino Lewis rats by increasing the intraocular pressure to 110 mm Hg for 45 minutes via an intracameral catheter. A total of 800 ng of bFGF was delivered into the anterior chamber at the time of induction of ischemia. Sixteen eyes of nine rats received bFGF, and 13 eyes of eight rats received heparin in phosphate- buffered saline as vehicle control. The animals were euthanized 7 or 14 days after reperfusion. Results. Morphologic examination of the retinas at both time points showed that necrosis of the retinal ganglion cells (RGCs) and thinning of the inner plexiform and inner nuclear layers were less severe in the bFGF-treated eyes than in the vehicle-treated eyes. On morphometric examination, 7 days after reperfusion, the mean thickness of the inner retinal layers and the RGC counts on flat preparations of retina in both the posterior and the peripheral portions of the retina were significantly higher in the bFGF-treated eyes than in the vehicle-treated eyes (P < .02). At 14 days, similar beneficial effects were noted in all morphometric parameters, except RGC counts in the posterior pole. Conclusions. These results demonstrate that bFGF partially protects the RGCs and other inner retinal elements from ischemic injury.