BASIC FIBROBLAST GROWTH-FACTOR TREATMENT PARTIALLY PROTECTS FROM VISUAL DEFICITS BUT DOES NOT INCREASE RETINAL GANGLION-CELL SURVIVAL FOLLOWING CONTROLLED OPTIC-NERVE CRUSH

Lack of trophic support after axonal injury leads to the degeneration of neurons. To study whether the application of trophic factor can imp rove functional recovery and retinal ganglion cell (RGC) survival afte r unilateral controlled optic nerve crush injury, we have now treated adult rats intraocularly (i.o.) with basic fibroblast growth factor (b FGF). To monitor visual deficits, rats were trained in a two-choice pa ttern discrimination test. Immediately after the crush, and on postope rative days 3 and 6, either 1.1 mu g recombinant bFGF or phosphate buf fered saline (PBS) was injected i.o. Sham-operated controls received i ntraocular injection of PBS or bFGF. Within the first few days after t he crush, all animals showed a loss of discrimination ability which wa s followed by a significant recovery within 2-3 weeks. Animals treated with bFGF had a significantly smaller initial deficit and thus recove red earlier compared to PBS controls. Retrograde RGC death was evaluat ed using retrograde HRP-tracing technique, but bFGF-treatment had no n europrotective effect. Thus, the behavioral effects of bFGF could not be related to neuroprotection of RGCs and therefore other mechanisms m ay have to be considered.