Abstract
Abstract: :
Purpose: To investigate the survival, integration and differentiation of fetal human retinal cells after subretinal transplantation to adult normal rats. Methods: Fetal human retina (embryonic day 89) was dissected, dissociated, and cultured for 2 months (kind gift of T.Reh, Seattle; Kelley et al. IOVS 1995:36:1280). The cells were then freezed until the time of transplantation. Normal non-immunosuppressed SD rats were subretinally transplanted with 50.000 cells and sacrificed at different intervals ranging from 1 hr to 5 weeks. The eyes were enucleated, fixated, embedded and cryostat sectioned for histology and immunohistochemistry. Results: Identified with anti-human nuclear protein (hNuc) and neuronal marker (hTau), grafted cells were found in the subretinal space one hour after transplantation. One to two weeks post-grafting, a huge amount of proliferating hNuc and hTau expressing cells were found in the choroid and conjunctiva. After three weeks the amount of grafted cells had decreased and 5 weeks post-transplantation only one rat out of 22 contained many implanted cells. Seven rats in the five-week group showed no sign of living transplanted cells. The transplantation of human cells caused the formation of granulation tissue, with neovascularization and invasion of PMN cells, within the conjunctiva. This reactive, non-neoplastic tissue seemed to disappear over time and only fibrotic scar tissue was found in the five-week group. The surviving cells did not show any sign of neuronal or glial differentiation with the antibodies used. Conclusions: Our results show that fetal human retinal cells can survive for a limited time in the rat eye. However, the cells cause a huge non-neoplastic reaction in the choroid and the conjunctiva, and they do not differentiate judged from immunohistochemical examination with various antibodies.
Keywords: transplantation • retina • immunohistochemistry