A Chick Model of Retinal Detachment: Cone Rich and Novel

Abstract

BackgroundDevelopment of retinal detachment models in small animals can be difficult and expensive. Here we create and characterize a novel, cone-rich retinal detachment (RD) model in the chick.Methodology/Principal FindingsRetinal detachments were created in chicks between postnatal days 7 and 21 by subretinal injections of either saline (SA) or hyaluronic acid (HA). Injections were performed through a dilated pupil with observation via surgical microscope, using the fellow eye as a control. Immunohistochemical analyses were performed at days 1, 3, 7, 10 and 14 after retinal detachment to evaluate the cellular responses of photoreceptors, Müller glia, microglia and nonastrocytic inner retinal glia (NIRG). Cell proliferation was detected with bromodeoxyuridine (BrdU)-incorporation and by the expression of proliferating cell nuclear antigen (PCNA). Cell death was detected with terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). As in mammalian models of RD, there is shortening of photoreceptor outer segments and mis-trafficking of photoreceptor opsins in areas of RD. Photoreceptor cell death was maximal 1 day after RD, but continued until 14 days after RD. Müller glia up-regulated glial fibriliary acidic protein (GFAP), proliferated, showed interkinetic nuclear migration, and migrated to the subretinal space in areas of detachment. Microglia became reactive; they up-regulated CD45, acquired amoeboid morphology, and migrated toward outer retina in areas of RD. Reactive NIRG cells accumulated in detached areas.Conclusions/SignificanceSubretinal injections of SA or HA in the chick eye successfully produced retinal detachments and cellular responses similar to those seen in standard mammalian models. Given the relatively large eye size, and considering the low cost, the chick model of RD offers advantages for high-throughput studies.

The chick eye in vision research: An excellent model for the study of ocular disease

“…Despite some anatomic differences in the retina compared with humans and other mammals, the biologic responses in chick RD were similar (Cebulla et al, 2012; Fisher et al, 2005; Lewis et al, 2002; Sethi et al, 2005). Retinal responses to RD included Müller glia proliferation, migration, and increased expression of the intermediate filaments, photoreceptor apoptosis and opsin mistrafficking, outer segment degeneration, loss of outer nuclear layer thickness in detached areas, blunting of the retinal pigment epithelium (RPE), and macrophage accumulation in areas of damage were observed (Cebulla et al, 2012).…”

“…Despite some anatomic differences in the retina compared with humans and other mammals, the biologic responses in chick RD were similar (Cebulla et al, 2012; Fisher et al, 2005; Lewis et al, 2002; Sethi et al, 2005). Retinal responses to RD included Müller glia proliferation, migration, and increased expression of the intermediate filaments, photoreceptor apoptosis and opsin mistrafficking, outer segment degeneration, loss of outer nuclear layer thickness in detached areas, blunting of the retinal pigment epithelium (RPE), and macrophage accumulation in areas of damage were observed (Cebulla et al, 2012). Additionally, the time-course of these changes, particularly with the preservation of the ONL until seven to 14 days post-detachment, fits well with what is known about human retinal detachments (Davidorf et al, 1975; Diederen et al, 2007; Hassan et al, 2002; Ross, 2002; Ross and Kozy, 1998; Salicone et al, 2006), in contrast to some experimental RD models like rabbits which have more rapid and severe photoreceptor degeneration (Fisher et al, 2005; Lewis et al, 2002).…”

“…For example, Pilar et al (1987) demonstrated in ex vivo studies that the nicotinic antagonist alpha bungarotoxin reduced pupil contraction force more than atropine 0.5% in postnatal birds and that the combination of drugs effectively blocked electrically-induced pupil constriction, more than nicotinic antagonist alone. Moderate dilation for ophthalmic procedures requiring bright illumination has been achieved with the nicotinic antagonist turbocurarine in 0.1% benzalkonium-containing solution (Cebulla et al, 2012). However, a triple combination of this agent with a muscarinic antagonist and adrenergic agonist might improve dilation responses.…”

“…A model for rhegmatogenous RD has also been by established by Cebulla et al (2012) using subretinal injections of hyaluronic acid to detach the retina. Despite some anatomic differences in the retina compared with humans and other mammals, the biologic responses in chick RD were similar (Cebulla et al, 2012; Fisher et al, 2005; Lewis et al, 2002; Sethi et al, 2005).…”

Differential Expression of AQP1 and AQP4 in Avascular Chick Retina Exposed to Moderate Light of Variable Photoperiods

“…For negative control, sections were processed by omitting with primary antibody step or preadsorption of the antibodies (1 lg/ml) with respective control peptides (5 lg/ml; AQP1 peptide, Geentree Biolab, Delhi, India and AQP4 peptide, catalog number 46161; Abcam Plc, UK) and subsequent treatment in the same protocol as already outlined. The GFAP antibody used in this study was used earlier in another study with chick retina [39].…”