Introducing a new model for studying retinal detachment/replacement: an electron microscopic study

ABSTRACT

Retinal detachment, separation of the neurosensory retina from the underlying retinal pigment epithelium, is a sight threatening condition that is considered one of the few ocular emergencies. In the current experiment, electron microscopic study of the retina of toad buffo marienes was done to evaluate the morphological changes due to retinal detachment and the possibility of spontaneous reattachment and to confirm the possibility of the use of the toad retina as a model for retinal detachment studies in mammals. The study focused on the retinal pigment epithelium and the outer segment of the neural retina. The retinal pigment epithelium of the control retina expressed the main features of the cells including the apical processes, the melanin granules and the phagosomes. The apical processes were firmly interdigitating with the neural retina outer segment and the melanin granules appear near the apical part of the cells. The outer segment of the neural retina appeared with parallel plates of flattened membranous desks. At 30 minutes after retinal detachment, a subretinal space appeared and the interdigitation between the processes of retinal pigment epithelium and the outer segment of the neural retina was lost. Two hours after retinal detachment, no continuity appeared between the retinal pigment epithelium and the outer segment of the neural retina. At 5 and 10 hours after retinal detachment, the interdigitation between the retinal pigment epithelium and the outer segment of the neural retina was restored. The tight junctions between different neural retina outer segments appeared to be not affected. In the current experiment, a simple model for experimental study of retinal pigment epithelium, neural retina and retinal detachment has been introduced. Due to the ultrastructural similarities of toad retinal pigment epithelium with that of mammals, the toad can serve as an excellent model for the study of retinal detachment/reattachment and their cellular and molecular mechanisms