Optical Coherence Tomography of Retinal Degeneration in Royal College of Surgeons Rats and Its Correlation with Morphology and Electroretinography

Abstract

PurposeTo evaluate the correlation between optical coherence tomography (OCT) and the histological, ultrastructural and electroretinography (ERG) findings of retinal degeneration in Royal College of Surgeons (RCS-/-) rats.Materials and MethodsUsing OCT, we qualitatively and quantitatively observed the continual retinal degeneration in RCS-/- rats, from postnatal (PN) day 17 until PN day 111. These findings were compared with the corresponding histological, electron microscopic, and ERG findings. We also compared them to OCT findings in wild type RCS+/+ rats, which were used as controls.ResultsAfter PN day 17, the hyperreflective band at the apical side of the photoreceptor layer became blurred. The inner segment (IS) ellipsoid zone then became obscured, and the photoreceptor IS and outer segment (OS) layers became diffusely hyperreflective after PN day 21. These changes correlated with histological and electron microscopic findings showing extracellular lamellar material that accumulated in the photoreceptor OS layer. After PN day 26, the outer nuclear layer became significantly thinner (P < 0.01) and hyperreflective compared with that in the controls; conversely, the photoreceptor IS and OS layers, as well as the inner retinal layers, became significantly thicker (P < 0.001 and P = 0.05, respectively). The apical hyperreflective band, as well as the IS ellipsoid zone, gradually disappeared between PN day 20 and PN day 30; concurrently, the ERG a- and b-wave amplitudes deteriorated. In contrast, the thicknesses of the combined retinal pigment epithelium and choroid did not differ significantly between RCS-/- and RCS+/+ rats.ConclusionOur results suggest that OCT demonstrates histologically validated photoreceptor degeneration in RCS rats, and that OCT findings partly correlate with ERG findings. We propose that OCT is a less invasive and useful method for evaluating photoreceptor degeneration in animal models of retinitis pigmentosa.

A new immunodeficient retinal dystrophic rat model for transplantation studies using human-derived cells

“…Consistent with the histology data, ERG testing (scotopic and photopic) also demonstrated progressive attenuation of retinal visual activity that became almost undetectable by the age of 4 months. The above pattern of visual function loss is comparable to the previous observations in non-immunodeficient RCS rats [64][65][66]. Electrophysiological mapping of the SC also revealed loss of visual function as reported in earlier investigations using non-immunodeficient RCS rats [43,44,67].…”

Oral levodopa rescues retinal morphology and visual function in a murine model of human albinism

“…Optical coherence tomography (OCT) is a non‐invasive imaging method that provides high‐resolution cross‐sectional images of in vivo retinal morphology (Adachi et al, ; Gabriele et al, ). Retinal OCT imaging has been correlated with histological, ultrastructural and electroretinography findings and has the significant advantage of facilitating longitudinal evaluation of disease progression (Adachi et al, ; Spaide & Curcio, ; Vajzovic et al, ). The effects of a 28‐day course of oral L‐DOPA supplementation on in vivo retinal development and morphology were investigated using OCT imaging (Leica Envisu R2200 Mouse Imaging System) (Figure ).…”

“…Optical coherence tomography (OCT) is a non-invasive imaging method that provides high-resolution cross-sectional images of in vivo retinal morphology (Adachi et al, 2016;Gabriele et al, 2011).…”

“…Retinal OCT imaging has been correlated with histological, ultrastructural and electroretinography findings and has the significant advantage of facilitating longitudinal evaluation of disease progression (Adachi et al, 2016;Spaide & Curcio, 2011;Vajzovic et al, 2012).…”

Angiographic and structural imaging using high axial resolution fiber-based visible-light OCT

“…The distinct boundaries of each layer better illustrate the structure of the retina and makes segmentation easier. Compared to imaging by systems operating at longer wavelengths [39,45], retinal imaging exhibited some unique features in vis-OCT. Increased layer contrast was obtained owing to the stronger interaction between light and tissue, caused by the relative high scattering coefficient of tissue in the visible range.…”