Topography Of Retinal Ganglion Cells Of The Pig Retina – Cell Size Distribution

Abstract

Abstract: : Purpose:To elaborate a precise topographic map of adult porcine retinal ganglion cells (RGCs), by analyzing the density and distribution of the different types of RGCs, classified on the basis of their soma size. Methods:Adult porcine RGCs were retrogradely labeled in vivo by injecting Fluorogold into the optic nerve. We classified the RGCs into three groups on the basis of the size of their soma, in small, medium and large. Morphometric analyses of RGC density, mean soma area and distribution of the different size groups were performed. Results:Three principal regions of the porcine retina can be defined in terms of RGC density: the visual streak, which is a high–density band (2,641 ± 149 RGCs/mm²) located dorsal to the optic disc; the mid–periphery, which is a vast region with medium cell density (678 ± 20 RGCs/mm²) and the periphery, which presents the lowest density of RGCs (241 ± 19 RGCs/ mm²). The mean RGC soma area was smaller in the visual streak (214 ± 5 mm²) than in the periphery (326 ± 7 mm²). Finally, analysis of the distribution of different types of RGCs showed that large RGCs are mainly distributed at the periphery (where they represent 65 ± 2.7% of cells), whereas in the visual streak, the majority of RGCs are small or medium–sized (30 ± 1.8% and 51 ± 1.3% of cells, respectively). Conclusions:In the present study, we present a detailed topography or RGCs in the porcine retina. This data provides an essential basis for the evaluation of RGC death in future studies involving the experimental induction of retinal pathologies using this animal model.

Keywords: ganglion cells • retina: proximal (bipolar, amacrine, and ganglion cells) • retina