Abstract
Abstract: :
Purpose: To study the survival of cultured transplanted adult neuroretina as a potential treatment for retinal degenerative disease. Methods: Six eyes were enucleated from adult pigs. One eyecup was fixated immediately, and from the remaining eyes, the neuroretina was dissected. Four retinal pieces, measuring 3–4 mm in diameter, were dissected from the central part of each eye. The twenty retinal explants were put in culture and kept in vitro under standard culture conditions. The cultured explants were divided into 3 groups, and kept in culture 1, 2 or 3 days. After the culture period, 12 explants were transplanted to the subretinal space of 12 adult normal pigs. The remaining explants were fixated and used as controls. After a survival of 72–74 days the transplanted eyes were enucleated and processed for hematoxylin and eosin staining and immunohistochemistry. Antibodies against transducin (cones), recoverin (cones and rods), and vimentin (Muller cells) were used. Results: Transplants kept 1 day in vitro (div) prior to transplantation, displayed the normal retinal lamination in 2 out of 4 specimens. In these transplants the nuclear and plexiform layers were clearly distinguished. The photoreceptors showed inner segments, and occasionally short outer segments. The third transplant was partly laminated, but displayed degeneration in its major part. The forth transplant had degenerated without any signs of lamination. Labelling for transducin and recoverin showed staining of photoreceptors with well–distinguished inner segments in the laminated grafts, and vimentin labelling revealed vertically arranged Müller cells in the laminated grafts. One of the eyes with a transplant, kept 2 div prior to transplantation, displayed a retinal detachment and no transplant could be found in this eye. In the 3 remaining transplants, of this group, two displayed minimal lamination. The fourth transplant had degenerated. Eyes, with transplants kept 3 div prior to transplantation displayed degenerated transplants in all 4 eyes, but dispersed cells labelled for transducin and recoverin could be identified. Control explants displayed normal nuclear layers, however the inner segments deteriorated with longer times in vitro. Conclusions: To our knowledge, this is the first study describing transplantation of cultured adult neuroretinal tissue. The study shows that it is possible to keep the adult retina in culture for at least 1 day prior to transplantation. This indicates a possibility to safely store donor tissue between harvest and actual transplantation. The culture system may also in the future be used as a tool for manipulating retinal donor tissue prior to transplantation.
Keywords: transplantation • retinal culture • retina: distal (photoreceptors, horizontal cells, bipolar cells)