Browsing by Subject "Displaced amacrine cells"

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    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
    (Elsevier, 2015-01-07) Ortín Martínez, Arturo; Jiménez López, Manuel; Valiente Soriano, Francisco Javier; García Ayuso, Diego; Bernal Garro, José Manuel; Avilés Trigueros, Marcelino; Agudo Barriuso, Marta; Villegas Pérez, María Paz; Vidal Sanz, Manuel; Salinas Navarro, Manuel Ángel; Nadal-Nicolás, Francisco Manuel; Oftalmología, Optometría, Otorrinolaringología y Anatomía Patológica
    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.
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    Open Access
    Long-term effect of optic nerve axotomy on the retinal ganglion cell layer
    (Association for Research in Vision and Ophthalmology., 2015-09-01) Nadal-Nicolás, Francisco Manuel; Sobrado Calvo, Paloma; Jiménez López, Manuel; Vidal Sanz, Manuel; Agudo Barriuso, Marta; Oftalmología, Optometría, Otorrinolaringología y Anatomía Patológica; Facultades de la UMU::Facultad de Medicina
    Purpose: To analyze the long-term effect of optic nerve injury on retinal ganglion cells (RGCs) and melanopsin+RGCs orthotopic and displaced, and on the rest of the ganglion cell layer (GCL) cells. Methods: In adult albino rats, the left optic nerve was crushed (ONC) or transected (ONT). Injured and contralateral retinas were analyzed at increasing survival intervals (up to 15 months). To study all GCL cells and RGCs, retinas were immunodetected with Brn3a and melanopsin to identify the general RGC population (Brn3a+) and m+RGCs, and counter-stained with 4′,6-diamidino-2-phenylindole (DAPI). Brn3a+RGCs and m+RGCs displaced to the inner nuclear layer were analyzed as well. In additional retinas, glial cells in the GCL were identified with glial fibrillary acidic protein (GFAP) or Iba1, and in some retinas, Brn3a, calretinin, and γ-synuclein were immunodetected. Results: Orthotopic and displaced RGCs behave similarly within the RGC and m+RGC populations. Both lesions cause an exponential loss of RGCs (4%–1% survival at 6 months after ONC or ONT), but not of m+RGCs, whose number remains stable from 1 to 15 months (34%–44% of the initial population). γ-synuclein is expressed by RGCs and displaced amacrine cells (dACs), allowing us to confirm that axotomy does not affect the latter, and to determine that out of the approximately 217,406 cells that compose the GCL (excluding endothelia), 10% are glial cells, 50% dACs, and the remaining 40% are RGCs. Conclusions: In the GCL, only RGCs are lost after axotomy, and there are important differences in the course of loss and rate of survival between melanopsin+RGCs and the rest of RGCs.