A Battery of Cell- and Structure-specific Markers for the Adult Porcine Retina.

The pig is becoming an increasingly used non-primate model in experimental studies of human retinal diseases and disorders. The anatomy, size, and vasculature of the porcine eye and retina closely resemble the human counterparts, which allows for application of standard instrumentation and diagnostics used in the clinic. Despite the many reports demonstrating immunohistochemistry as a useful method for exploring neuropathological changes in the mammalian central nervous system, including the pig, the porcine retina has been sparsely described. Hence, to facilitate further immunohistochemical analysis of the porcine retina we here report on the successful use of a battery of antibodies for staining of paraformaldehyde fixed cryosectioned retina. The following antibodies were evaluated for neuronal cells and structures: recoverin (cones and rods), Rho4D2 (rods), transducin-gamma (cones), ROM-1 (photoreceptor outer segments), calbindin (horizontal cells), PKC-alpha (bipolar cells), parvalbumin (amacrine- and displaced amacrine cells), NeuN (ganglion cells, displaced amacrines). For detecting synaptic connections in fibre layers an antibody against synaptobrevin was used. For detecting the retinal pigment epithelium antibodies against cytokeratin and RPE65, respectively, were studied. The glial cell markers used were: bFGF (Müller cells and displaced amacrine cells), GFAP (Müller cells and astrocytes), and vimentin (Müller cells). Each staining was evaluated with regard to its specificity, sensitivity, and reproducibility in the identification of individual cells, specific cell structures and fiber layers, respectively. The markers parvalbumin and ROM-1 were tested here for the first time for the porcine retina. All antibodies tested resulted in specific staining of high quality. In conclusion, all immunohistochemical protocols presented here will be applicable in fixed cryosectioned pig retina.