PHOTORECEPTOR TRANSPLANTS INCREASE HOST CONE SURVIVAL IN THE RETINAL DEGENERATION (RD) MOUSE

Retinal transplants offer a potentially interesting approach to treati ng human retinal degenerations, but so far little quantitative data ar e available on possible beneficial effects, We isolated photoreceptor layers from normal-sighted mice and grafted them into the subretinal s pace of retinal degeneration (rd) mice lacking rod photoreceptors, At 2 weeks after surgery, the numbers of residual host cone photoreceptor s outside the graft zone were quantified following specific labelling. Examination of operated retinas revealed highly significantly greater numbers of surviving cones (mean of 38% more at 2 weeks) within the c entral field compared to sham-operated paired control retinas (p < 0.0 1), These are the first quantified data indicating a trophic effect of transplanted photoreceptors upon host cone cells. As cone cells are r esponsible for high acuity and colour vision? such data could have imp ortant implications not only for eventual therapeutic approaches to hu man retinal degenerations but also to understanding underlying interac tions between retinal photoreceptors.