Retinal Ganglion Cells From Human and Porcine Retina. Many Similarities and Few Diferences

Abstract

Abstract: : Purpose: To validate the porcine retina as a model with a very similar characteristics to the human retina with respect to the expression of the neurotrophins and their receptors. To characterise if the porcine RGCs types are similar to human cells in terms of size and cytoskeleton. Methods:Retinas from adult pigs and human donors were immunostained in sections and whole mount with antibodies against the neurotrophins: nervous growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin 3 and 4 (NT3, NT4) and their respective high affinity receptors TrkA, TrkB, TrkC and the low affinity receptor p75. In addition, to identify and classify the pig RGCs, they were retrogradly labelled with fluorogold from the optic nerve and then immunolabelled with the three neurofilament antibodies against the low (68KD), medium (160) and heavy (200KD) molecules. Results: We found a very similar expression in the neurotrophins and their receptors between the porcine and the human retina. Moreover, the human as well as the pig RGCs in vivo express the three different neurofilament subunits. Three different RGCs sizes can clearly be identified in based on the length of their major axis: Small RGCs (9-14 mm); medium-sized RGCs (15-20 mm) and large RGCs (>20 mm). Conclusions: The porcine retina is very similar to the human retina in terms of expression of neurotrophins and their receptors. Moreover the neurofilaments staining and the retrograde labelling with fluorogold of the RGCs in pig, let us to identify three different sizes of RGCs as occurs in the human retina.

Keywords: retina • ganglion cells • animal model