Cone photoreceptors in laminated retinal transplants

Purpose: To investigate the contents of green- and blue-sensitive cone phot oreceptors in laminated rabbit retinal transplants. Methods: Eleven rabbits each received a sheet of embryonic neuroretina into the subretinal space in one eye. Vitrectomy was used in the procedure and properly polarized flat transplants were placed on the host pigment epithel ium. After 17-309 days the transplants were examined immunohistochemically with specific antibodies against COS-1 (green-sensitive cones) and OS-2 (bl ue-sensitive cones). Results: All grafts displayed normal lamination with well developed photore ceptor outer segments apposed to the host retinal pigment epithelium. Occas ionally, rosettes were found at the transplant edges. Both COS-1 positive a nd OS-2 positive cones were detected. In the laminated part of the grafts, COS-1 positive cones were more numerous than OS-2 positive ones. In the ros etted parts of the transplants the relationship between the cones was rever sed. Conclusion: Full-thickness embryonic rabbit retinal transplants develop int o laminated retinas with well-developed photoreceptor outer segment. Both g reen- and blue-sensitive cone photoreceptors are present and the ratio betw een the two cone types is the same as in the normal adult rabbit retina.