Mohamad A Khodair1, Marco A Zarbin, Ellen Townes-Anderson. 1. Department of Neurosciences, Graduate School of Biomedical Sciences, University of Medicine and Dentistry of New Jersey, Newark, New Jersey 07103, USA. khodaimo@umdnj.edu
Abstract
PURPOSE: To investigate systematically the early morphologic changes in axon terminals of adult mammalian rod and cone photoreceptors prepared as a sheet for subretinal transplantation. METHODS: An in vitro system was designed to maintain adult porcine retinas for up to 48 hours. Photoreceptor sheets, prepared by vibratome sectioning, and full-thickness retinas were cultured at temperatures similar to those in pretransplantation storage (4 degrees C) and after transplantation (37 degrees C). Changes in the outer nuclear and outer plexiform layers were analyzed, using immunohistochemistry, laser scanning confocal microscopy, and image analysis. RESULTS: Morphologic changes were observed in photoreceptor sheets as early as 10 minutes after incubation. The most significant change was the retraction of photoreceptor axons and terminals toward their cell bodies. Retraction was temperature dependent, being exacerbated at 37 degrees C compared with 4 degrees C, at its maximum by 24 hours of culture, and present in sheets obtained from both superior and inferior retina. The cause of this movement was not preparation techniques associated with vibratome sectioning or gelatin removal. Retraction was also present in full-thickness neural retina incubated at 37 degrees C. Reduction in outer nuclear layer cell counts and thickness were also evident in these preparations, primarily in photoreceptor sheets. CONCLUSIONS: Adult photoreceptor sheets, a potential graft preparation for retinal transplantation, show a rapid retraction of axon terminals toward the cell bodies during culture. Although retraction may impede synaptic integration after transplantation, this intrinsic plasticity could be redirected to stimulate graft-host interaction.
PURPOSE: To investigate systematically the early morphologic changes in axon terminals of adult mammalian rod and cone photoreceptors prepared as a sheet for subretinal transplantation. METHODS: An in vitro system was designed to maintain adult porcine retinas for up to 48 hours. Photoreceptor sheets, prepared by vibratome sectioning, and full-thickness retinas were cultured at temperatures similar to those in pretransplantation storage (4 degrees C) and after transplantation (37 degrees C). Changes in the outer nuclear and outer plexiform layers were analyzed, using immunohistochemistry, laser scanning confocal microscopy, and image analysis. RESULTS: Morphologic changes were observed in photoreceptor sheets as early as 10 minutes after incubation. The most significant change was the retraction of photoreceptor axons and terminals toward their cell bodies. Retraction was temperature dependent, being exacerbated at 37 degrees C compared with 4 degrees C, at its maximum by 24 hours of culture, and present in sheets obtained from both superior and inferior retina. The cause of this movement was not preparation techniques associated with vibratome sectioning or gelatin removal. Retraction was also present in full-thickness neural retina incubated at 37 degrees C. Reduction in outer nuclear layer cell counts and thickness were also evident in these preparations, primarily in photoreceptor sheets. CONCLUSIONS: Adult photoreceptor sheets, a potential graft preparation for retinal transplantation, show a rapid retraction of axon terminals toward the cell bodies during culture. Although retraction may impede synaptic integration after transplantation, this intrinsic plasticity could be redirected to stimulate graft-host interaction.
Authors: Kristan S Worthington; Luke A Wiley; Alexandra M Bartlett; Edwin M Stone; Robert F Mullins; Aliasger K Salem; C Allan Guymon; Budd A Tucker Journal: Exp Eye Res Date: 2014-03-05 Impact factor: 3.467