es of how to cure RP (Cayouette et al., 1-2).
             Series of tests have been conducted on RP (retinal degeneration) mice and have determined that rd photoreceptors can be salvaged by inserting wild-type copies of a phosphodiesterase gene. Even though this strategy proved to be quite useful, other theories had to be thought up since the efficiency of gene transfer was limited. Another strategy was finding the source of the problem of all RP-causing deformities found in the animals, which was the death of photoreceptors. Neurotrophic factors have been discovered that results in the prevention of programmed cell death in vitro and in vivo neuronal populations. Intravitreal direction of trophic factors proved to the loss of photoreceptors in rats. In the rd mouse, it was discovered that if there was an intraocular increase in NGF or CNTF could drastically reduce the rate of photoreceptor loss. Nevertheless, whether or not those recovered photoreceptors still function properly is what was to be determined (Cayouette et al., 2).
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