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Abstract #18925 Published in IGR 3-1
Selective excitotoxic degeneration of adult pig retinal ganglion cells in vitro
Luo X; Heidinger V; Picaud S; Lambrou GN; Dreyfus H; Sahel J; Hicks DInvestigative Ophthalmology and Visual Science 2001; 42: 1096-1106
PURPOSE: Excitotoxicity is proposed to play a prominent role in retinal ganglion cell (RGC) death ensuing from diseases such as glaucoma and ischemia, but cell culture studies have used tissue from newborn rodents, yielding conflicting data that implicate either N:-methyl D-aspartate (NMDA) or non-NMDA glutamate (Glu) receptor-mediated pathways. Excitotoxic RGC death was examined in vitro in this study, using adult pigs, a large-animal model for human retina. METHODS: Adult pig retina (and for comparative purposes young and adult rat retina) were dissociated and maintained in monolayer culture. Medium was supplemented with Glu or pharmacologic agonists or antagonists, and surviving RGCs and other retinal neurons were quantified using specific immunolabelling methods. Electrophysiological responses to externally applied Glu of RGCs in culture were recorded using whole-cell patch-clamp techniques. RESULTS: Application of Glu led to selective, dose-dependent losses in large RGCs (maximal 37% decrease at 1 mM; median effective dose (ED50), approximately 80 mM) and neurite damage in surviving RGCs. Application of Glu agonists and Glu receptor subclass antagonists showed that large RGC death was mediated through both NMDA and non-NMDA receptor pathways. Small RGCs, amacrine cells, and all other retinal neurons were resistant to Glu-induced death. By comparison, rat retinal cultures displayed heightened RGC vulnerability to Glu, mediated exclusively by non-NMDA receptor-mediated pathways. Amacrine cells were unaffected by NMDA but were very sensitive to kainate application (>90% loss). Other retinal neurons were unaffected by any treatment. CONCLUSIONS: The molecular pathways underlying excitotoxic RGC death in vitro (non-NMDA or NMDA-preferring Glu receptors) vary among species and developmental stages. The selective elimination of adult pig large RGCs by NMDA receptor-mediated pathways more closely resembles human and animal glaucoma in vivo than other published culture models, providing a simplified experimental system for investigating the pharmacological and toxicological bases of glaucoma-like neuronal death.
Dr X Luo, Laboratoire de Physiopathologie Cellulaire et Moleculaire de la Retine, Institut National de la Sante et de la Recherche Medicale, Université Clinique Medicale A, Centre Hospitalier et Universitaire, Strasbourg, France
Classification:
1.3 Pathogenesis (Part of: 1 General aspects)
