Browsing by Subject "Retinal nerve fiber layer"

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    Comparison of retinal nerve fiber layer thinning and retinal ganglion cell loss after optic nerve transection in adult albino rats
    (Association for Research in Vision and Ophthalmology., 2015-07-15) Rovere, Giuseppe; Nadal-Nicolás, Francisco Manuel; Agudo Barriuso, Marta; Sobrado Calvo, Paloma; Nieto López, Leticia; Nucci, Carlo; Villegas Pérez, Maria Paz; Vidal Sanz, Manuel; Oftalmología, Optometría, Otorrinolaringología y Anatomía Patológica; Facultades de la UMU::Facultad de Medicina
    PURPOSE. We compared the time-course and magnitude of retinal nerve fiber layer (RNFL) thinning with that of retinal ganglion cell (RGC) loss after intraorbital optic nerve transection (IONT) in adult rats. METHODS. At 3, 7, 12, or 21 days, or 1, 2, or 4 months after ONT, the retinas were imaged with spectral-domain optical coherence tomography (SD-OCT) using the circular-peripapillary scan and volume scan raster pattern (61 horizontal sections equally spaced) both centered in the optic nerve. In all sections, the RNFL and retinal thickness were measured to obtain the total values of the peripapillary scan and the values of three concentric sectors (400, 1200, and 2400 lm in diameter) from the volume scan. After SD-OCT, retinas were dissected and immunoreacted for Brn3a and neurofilaments (pNFH) to identify RGCs and their intraretinal axons, respectively. Total numbers of RGCs were quantified. RESULTS. Thinning of the RNFL was first observed at 12 days in peripapillary scan (10% decrease) and progressed up to 4 months (72% decrease). The volume scan showed transient RNFL swelling in central and medial sectors at 3, 7, and 12 days followed by progressive significant thinning first observed at 21 days (central sector, 30%; medial sector, 40%) and 12 days (peripheral sector, 15%), respectively. Following IONT, Brn3aþ RGCs decreased to approximately 80%, 52%, 17%, 9%, 5%, 3%, and 2% at 3, 7, 12, 21 days, and at 1, 2, and 4 months, respectively. Retinal ganglion cell axon immunodetection decreased from 12 days onwards. CONCLUSIONS. After IONT, RGC death is more severe and precedes thinning of the RNFL.
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    Shared and differential retinal responses against optic nerve injury and ocular hypertension
    (Frontiers Media SA., 2017-04-26) Vidal Sanz, Manuel; Galindo Romero, Caridad; Valiente-Soriano, Francisco J.; Nadal-Nicolás, Francisco Manuel; Ortín-Martínez, Arturo; Rovere, Giuseppe; Salinas Navarro, Manuel Ángel; Lucas Ruiz, Fernando; Sánchez-Migallón, María C.; Sobrado Calvo, Paloma; Avilés Trigueros, Marcelino; Villegas Pérez, Maria Paz; Agudo Barriuso, Marta; Oftalmología, Optometría, Otorrinolaringología y Anatomía Patológica; Facultad de Medicina
    Glaucoma, one of the leading causes of blindness worldwide, affects primarily retinal ganglion cells (RGCs) and their axons. The pathophysiology of glaucoma is not fully understood, but it is currently believed that damage to RGC axons at the optic nerve head plays a major role. Rodent models to study glaucoma include those that mimic either ocular hypertension or optic nerve injury. Here we review the anatomical loss of the general population of RGCs (that express Brn3a; Brn3a+RGCs) and of the intrinsically photosensitive RGCs (that express melanopsin; m+RGCs) after chronic (LP-OHT) or acute (A-OHT) ocular hypertension and after complete intraorbital optic nerve transection (ONT) or crush (ONC). Our studies show that all of these insults trigger RGC death. Compared to Brn3a+RGCs, m+RGCs are more resilient to ONT, ONC, and A-OHT but not to LP-OHT. There are differences in the course of RGC loss both between these RGC types and among injuries. An important difference between the damage caused by ocular hypertension or optic nerve injury appears in the outer retina. Both axotomy and LP-OHT induce selective loss of RGCs but LP-OHT also induces a protracted loss of cone photoreceptors. This review outlines our current understanding of the anatomical changes occurring in rodent models of glaucoma and discusses the advantages of each one and their translational value.