Characterization of retinal ganglion cells subtypes in the rat retina

Abstract

AbstractPurpose: Retinal ganglion cells (RGCs) are a heterogeneous population of neurons that propagates visual information to the brain. Glaucoma is a disease characterized by the selective death of RGCs, which induce a progressive and irreversible loss of vision. In glaucoma, not all RGCs subtypes are affected equally; however, a rigorous characterization has not been fully described. Thus, the aim of this work is to fully characterize and quantify different RGCs subtypes at different localizations in rat retinas.Methods: RGCs were labelled by immunochemistry in control rat whole‐mount retinas. Images were captured using the optic disc as a reference for the different retinal zones. RGCs were labelled with an antibody against RBPMS that is considered the 100% of RGCs, and co‐labelled with subtype‐specific antibodies against: CART, Islet1/2, TBR2, SPP1. After quantification, the percentage of RGCs of each subtype were calculated in relation to the total RBPMS positive cells.Results: In the rat retina, the density of RGCs was 1853/mm2 in centre, 2041/mm2 in middle‐centre, 1760/mm2 in middle‐periphery and 916/mm2 in periphery. CART was expressed in 31.2% of the RGCs from the centre, in 32.1% from the middle‐centre, in 33.3% from the middle‐periphery and in 27.8% from the periphery of the retina. Islet1/2 was expressed in 72.4% of the central RGCs, in 79.3% from the middle‐central RGCs, in 77.8% from the middle‐peripheral RGCs and in 72.4% from the peripheral RGCs of the retina. TBR2 was expressed in 11.4% of the RGCs from the centre, in 13.3% from the middle‐centre, in 12.8% from the middle‐periphery and in 16.1% from the periphery of the retina. SPP1 slightly marked the soma of almost 100% of total RGCs.Conclusions: There is a characteristic pattern for each RGCs subtype in the rat retina. Therefore, we will compare these results with the same analysis in a rat glaucoma model allowing us to elucidate which RGCs subtypes are most susceptible.Supported by ELKARTEK (KK‐2019/00086), MINECO‐Retos (PID2019‐111139RB‐I00) and PIBA (2020_1_0026).