Transplantation of Fetal Retinal Sheets in rd Mice

Abstract

Abstract: : Purpose: To evaluate the morphology and integration of sheets of fetal retina transplanted into the subretinal space of rd mice. Methods: rd (C3H/HeJ) mice (age 2-3 and 6 weeks) were transplanted in one eye with retinal sheets (1.0 x 0.4 mm) obtained from E17 or E18 normal enhanced-green-fluorescent protein (eGFP) mice using the method of Aramant & Seiler (Prog Retin Eye Res 21:57-73, 2002). Five weeks after transplantation, the eyes were enucleated and processed for immunohistochemistry. Sections were labeled with antibodies for opsin, rhodopsin, synaptophysin, synapsin I, protein kinase C, calbindin and cellular retinaldehyde binding protein (CRALBP). Results: GFP-labeled grafts could be identified as sheets of cells located in the subretinal space. In most of the grafts, staining for synaptic proteins (synaptophysin or synapsin) at the graft-host interface and extension of glial processes of the grafts into the host retinal layers were observed. However, these glial processes also sometimes formed a glial cell barrier. Two of the grafts showed clear lamination of layers exhibiting outer segment staining for opsin/rhodopsin. Three grafts contained rosettes staining for opsin/rhodopsin and five grafts contained disorganized layers. Conclusions: Compared with our previous studies in mice using retinal fragment suspensions, this technique of retinal sheet transplantation (previously only used in larger rat eyes) significantly enhanced the organization of the graft and integration at the graft-host interface. Some eyes did form a glial barrier at the interface, which appeared to derive from transplant and/or host. Support: NIH grant EY03040, Foundation Fighting Blindness, Foundation for Retinal Research, Fletcher Jones Foundation, Panitch Fund and Anonymous Sponsor.

Keywords: transplantation • retinal connections, networks, circuitry • retinal degenerations: cell biology