Ocular comparative anatomy of the family <scp>R</scp>odentia

Fernández, Julia Rodríguez-Ramos; Dubielzig, Richard R.

doi:10.1111/vop.12070

Cited by 37 publications

(23 citation statements)

References 9 publications

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“…Guinea pig retinal physiology, both in vitro single cell recordings 13, 14 and in vivo electrophysiology, 15, 16 have previously been characterized. Additionally, in vitro retinal and optic nerve head (ONH) structures in the guinea pig have been examined; 17, 18 however, in vivo methods to assess the retina, choroid and ONH have not yet been established.…”

Section: Introductionmentioning

confidence: 99%

In Vivo Imaging of the Retina, Choroid, and Optic Nerve Head in Guinea Pigs

Jnawali

Beach

Ostrin

2018

Current Eye Research

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Purpose Guinea pigs are increasingly being used as a model of myopia, and may also represent a novel model of glaucoma. Here, optical coherence tomography (OCT) imaging was performed in guinea pigs. In vivo measurements of retinal, choroidal and optic nerve head parameters were compared with histology, and repeatability and interocular variations were assessed. Methods OCT imaging and histology were performed on adult guinea pigs (n = 9). Using a custom program in Matlab, total retina, ganglion cell/nerve fiber layer (GC/NFL), outer retina and choroid thicknesses were determined. Additionally, Bruch’s membrane opening (BMO) area and diameter, and minimum rim width were calculated. Intraobserver, interocular and intersession coefficients of variation (CV) and intraclass correlation coefficients (ICC) were assessed. Results Retina, GC/NFL, outer retina and choroid thicknesses from in vivo OCT imaging were 147.7 ± 5.8 μm, 59.2 ± 4.5 μm, 72.4 ± 2.4 μm, and 64.8 ± 11.6 μm, respectively. Interocular CV ranged from 1.8 to 11% (paired t-test, p = 0.16 to 0.81), and intersession CV ranged from 1.1 to 5.6% (p = 0.12 to 0.82), with the choroid showing the greatest variability. BMO area was 0.192 ± 0.023 mm2, and diameter was 493.79 ± 31.89, with intersession CV of 3.3% and 1.7%, respectively. Hyper reflective retinal layers in OCT correlated with plexiform and RPE layers in histology. Conclusion In vivo OCT imaging and quantification of guinea pig retina and optic nerve head parameters were repeatable and similar between eyes of the same animal. In vivo visibility of retinal cell layers correlated well with histological images.

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Section: Introductionmentioning

confidence: 99%

In Vivo Imaging of the Retina, Choroid, and Optic Nerve Head in Guinea Pigs

Jnawali

Beach

Ostrin

2018

Current Eye Research

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“…The 13LGS mitochondrial genome has also recently been sequenced (Zhang et al, 2015). The markedly slow rate of evolution of GSs makes them useful for comparative genomics vis-à-vis rats and mice (reviewed by Rodriguez-Ramos Fernandez & Dubielzig, 2013). A retina-specific RNAseq database with 20,000 genes has also been acquired from the 13LGS (Wei Li, unpublished).…”

Section: Ground Squirrel Visual Systemmentioning

confidence: 99%

“…Hence, instead of a blind “spot” in its visual field, the GS will have a blind “band”, but its dorsal position does not interfere with images of the world above the ground (Rodriguez-Ramos Fernandez & Dubielzig, 2013). Dorsal from the horizontal nerve head, the outer nuclear layer (ONL) is 1–2 nuclei thick and the photoreceptor:ganglion cell ratio is 4:2, whereas the ventral ONL is 2–3 nuclei thick and the photoreceptor:ganglion cell ratio is only 3:2 (Rodriguez-Ramos Fernandez & Dubielzig, 2013; Vaidya, 1965). This retinal asymmetry has long been ascribed to the “danger above” posed by predators.…”

Section: Ground Squirrel Visual Systemmentioning

confidence: 99%

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Seasonal and post-trauma remodeling in cone-dominant ground squirrel retina

Merriman

Sajdak

et al. 2016

Experimental Eye Research

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With a photoreceptor mosaic containing ~85% cones, the ground squirrel is one of the richest known mammalian sources of these important retinal cells. It also has a visual ecology much like the human’s. While the ground squirrel retina is understandably prominent in the cone biochemistry, physiology, and circuitry literature, far less is known about the remodeling potential of its retinal pigment epithelium, neurons, macroglia, or microglia. This review aims to summarize the data from ground squirrel retina to this point in time, and to relate them to data from other brain areas where appropriate. We begin with a survey of the ground squirrel visual system, making comparisons with traditional rodent models and with human. Because this animal’s status as a hibernator often goes unnoticed in the vision literature, we then present a brief primer on hibernation biology. Next we review what is known about ground squirrel retinal remodeling concurrent with deep torpor and with rapid recovery upon re-warming. Notable here is rapidly-reversible, temperature-dependent structural plasticity of cone ribbon synapses, as well as pre- and post-synaptic plasticity throughout diverse brain regions. It is not yet clear if retinal cell types other than cones engage in torpor-associated synaptic remodeling. We end with the small but intriguing literature on the ground squirrel retina’s remodeling responses to insult by retinal detachment. Notable for widespread loss of (cone) photoreceptors, there is surprisingly little remodeling of the RPE or Müller cells. Microglial activation appears minimal, and remodeling of surviving second- and third-order neurons seems absent, but both require further study. In contrast, traumatic brain injury in the ground squirrel elicits typical macroglial and microglial responses. Overall, the data to date strongly suggest a heretofore unrecognized, natural checkpoint between retinal deafferentiation and RPE and Müller cell remodeling events. As we continue to discover them, the unique ways by which ground squirrel retina responds to hibernation or injury may be adaptable to therapeutic use.

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“…Astrocytes and oligodendrocytes represent the main non-neuronal, support component of the optic nerve head of rats and mice (Morcos and Chan-Ling, 2000). In a comprehensive study of OHN structures involving 18 different rodent species (Rodriguez-Ramos Fernandez and Dubielzig, 2013), the presence of an LC was confirmed in 4 species, including porcupine, capybara, flying squirrel and western gray squirrel, while the Norway rat and three species of mice were found to lack a LC. The lack of relevant histological sections of the optic nerve precluded evaluation of the LC for several species, including the guinea pig, which along with the mouse, also has application in myopia research.…”

Section: Introductionmentioning

confidence: 97%

Optic nerve head and intraocular pressure in the guinea pig eye

Ostrin

Wildsoet

2016

Experimental Eye Research

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The guinea pig is becoming an increasingly popular model for studying human myopia, which carries an increased risk of glaucoma. As a step towards understanding this association, this study sought to characterize the normal, developmental intraocular pressure (IOP) profiles, as well as the anatomy of the optic nerve head (ONH) and adjacent sclera of young guinea pigs. IOP was tracked in pigmented guinea pigs up to 3 months of age. One guinea pig was imaged in vivo with OCT and one with a fundus camera. The eyes of pigmented and albino guinea pigs (ages 2 months) were enucleated and sections from the posterior segment, including the ONH and surrounding sclera, processed for histological analyses - either hematoxylin and eosin (H&E) staining of paraffin embedded, sectioned tissue (n = 1), or cryostat sectioned tissue, processed for immunohistochemistry (n = 3), using primary antibodies against collagen types I-V, elastin, fibronectin and glial fibrillary acidic protein (GFAP). Transmission and scanning electron microscopy (TEM, SEM) studies of ONHs were also undertaken (n = 2 & 5 respectively). Mean IOPs ranged from 17.33 to 22.7 mmHg , increasing slightly across the age range studied, and the IOPs of individual animals also exhibited diurnal variations, peaking in the early morning (mean of 25.8, mmHg, ~9 am), and decreasing across the day. H&E-stained sections showed retinal ganglion cell axons organized into fascicles in the prelaminar and laminar region of the ONHs, with immunostained sections revealing collagen types I, III, IV and V, as well as elastin, GFAP and fibronectin in the ONHs. SEM revealed a well-defined lamina cribrosa (LC), with radially-oriented collagen beams. TEM revealed collagen fibrils surrounding non-myelinated nerve fiber bundles in the LC region, with myelination and decreased collagen posterior to the LC. The adjacent sclera comprised mainly crimped collagen fibers in a crisscross arrangement. Both the sclera and LC were qualitatively similar in structure in pigmented and albino guinea pigs. The well-organized, collagen-based LC of the guinea pig ONH is similar to that described for tree shrews and more similar to the human LC than that of other rodents that lack collagen. Based on these latter structural similarities the guinea pig would seem a promising model for investigating the relationship between myopia and glaucoma.

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Ocular comparative anatomy of the family Rodentia

Cited by 37 publications

References 9 publications

In Vivo Imaging of the Retina, Choroid, and Optic Nerve Head in Guinea Pigs

In Vivo Imaging of the Retina, Choroid, and Optic Nerve Head in Guinea Pigs

Seasonal and post-trauma remodeling in cone-dominant ground squirrel retina

Optic nerve head and intraocular pressure in the guinea pig eye

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