Photoreceptors Repair by Autologous Transplantation of Retinal Pigment Epithelium and Partial-Thickness Choroid Graft in Rabbits

PURPOSE. To investigate whether autologous retinal pigment epithelium (RPE) and a partial-thickness graft can repair degenerated photoreceptors overlying a mechanically damaged Bruch's membrane. METHODS. Twenty-one pigmented rabbits were used in the study. Abrasive debridement of the RPE was performed with a metal cannula after superior retinal bleb detachment in 20 rabbits. The graft was prepared beneath the inferior retina and was transplanted to the debridement area 14 days later. Debridement-only sites served as the control. Tissue sections were evaluated by light microscopy and transmission electron microscopy at 7 days, 1 month, and 3 months after transplantation, corresponding to 21 days, 45 days, and 3 months after debridement, respectively. RESULTS. When analyzed at 7 days after transplantation, short buds of inner segment with regularly organized outer nuclear layer were observed. The outer segments (OS) were of insufficient length to be observed, but by 1 and 3 months, a significant elongation of the OS was detected. In control retinas from 21 days (corresponding to 7 days after transplantation) to 3 months after RPE debridement, the outer nuclear layer cells were disorganized and diminished. CONCLUSIONS. This study showed that autologous RPE and partial-thickness choroid graft have the capacity not only to support photoreceptor cell survival, but also to initiate early repair mechanisms, as exhibited by outer segment regeneration. (Invest Ophthalmol Vis Sci. 2009; 50: 2982-2988) DOI: 10.1167/iovs.08-2131