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Abstract #60246 Published in IGR 16-4
Laser-induced ocular hypertension in adult rats does not affect non-RGC neurons in the ganglion cell layer but results in protracted severe loss of cone-photoreceptors
Ortín-Martínez A; Salinas-Navarro M; Nadal-Nicolás FM; Jiménez-López M; Valiente-Soriano FJ; García-Ayuso D; Bernal-Garro JM; Avilés-Trigueros M; Agudo-Barriuso M; Villegas-Pérez MP; Vidal-Sanz MExperimental Eye Research 2015; 132: 17-33
To investigate the long-term effects of laser-photocoagulation (LP)-induced ocular hypertension (OHT) in the innermost and outermost (outer-nuclear and outer segment)-retinal layers (ORL). OHT was induced in the left eye of adult rats. To investigate the ganglion cell layer (GCL) wholemounts were examined at 1, 3 or 6 months using Brn3a-immunodetection to identify retinal ganglion cells (RGCs) and DAPI-staining to detect all nuclei in this layer. To study the effects of LP on the ORL up to 6 months, retinas were: i) fresh extracted to quantify the levels of rod-, S- and L-opsin; ii) cut in cross-sections for morphometric analysis, or; iii) prepared as wholemounts to quantify and study retinal distributions of entire populations of RGCs (retrogradely labeled with fluorogold, FG), S- and L-cones (immunolabeled). OHT resulted in wedge-like sectors with their apex on the optic disc devoid of Brn3a(+)RGCs but with large numbers of DAPI(+)nuclei. The levels of all opsins diminished by 2 weeks and further decreased to 20% of basal-levels by 3 months. Cross-sections revealed focal areas of ORL degeneration. RGC survival at 15 days represented approximately 28% and did not change with time, whereas the S- and L-cone populations diminished to 65% and 80%, or to 20 and 35% at 1 or 6 months, respectively. In conclusion, LP induces in the GCL selective RGCs loss that does not progress after 1 month, and S- and L-cone loss that progresses for up to 6 months. Thus, OHT results in severe damage to both the innermost and the ORL.
Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), 30100 Murcia, Spain.
Full articleClassification:
5.1 Rodent (Part of: 5 Experimental glaucoma; animal models)
11.8 Neuroprotection (Part of: 11 Medical treatment)