Open AccessLongitudinal Structural and Microvascular Observation in RCS Rat Eyes Using Optical Coherence Tomography Angiography
Author(s) -
Bingyao Tan,
Veluchamy A Barathi,
Emily Lin,
Candice Ho,
Alfred Tau Liang Gan,
Xinwen Yao,
Amos Chan,
Damon Wing Kee Wong,
Jacqueline Chua,
Gary Tan,
Leopold Schmetterer
Publication year - 2020
Publication title -
investigative ophthalmology and visual science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.935
H-Index - 218
eISSN - 1552-5783
pISSN - 0146-0404
DOI - 10.1167/iovs.61.6.54
Subject(s) - retina , ophthalmology , retinal , retinitis pigmentosa , medicine , ganglion cell layer , optical coherence tomography angiography , ganglion , inner nuclear layer , optical coherence tomography , outer plexiform layer , inner plexiform layer , anatomy , outer nuclear layer , retinal pigment epithelium , biology , neuroscience
Purpose To evaluate the change of retinal thickness and ocular microvasculature in a rat model of retinitis pigmentosa using swept source optical coherence tomography angiography (SS-OCTA) Methods Three-weeks-old Royal College of Surgeons (RCS) rats ( n = 8) and age-matched control rats ( n = 14) were imaged by a prototype SS-OCTA system. Follow-up measurements occurred every three weeks on six RCS rats until week 18, and cross-sectional measurements were conducted on control rats. Thicknesses of different retinal layers and the total retina were measured. The enface angiograms from superficial vascular plexiform (SVP) and deep capillary plexiform (DCP) were analyzed, and the image sharpness was also extracted from the choroidal angiograms. Immunohistochemical analysis was done in the RCS rats after week 18, as well as in three-week-old RCS rats and age-matched controls. Results In RCS rats, the thicknesses of the ganglion cell complex, the nuclear layer, the debris/photoreceptor layer and the total retina decreased over the weeks ( P < 0.001). The SVP metrics remained unchanged whereas the DCP metrics decreased significantly over the weeks ( P < 0.001). The immunohistochemical analysis confirmed our OCTA findings of capillary dropout in the DCP. The choroidal plexus appeared indistinct initially due to scattering of light at the intact retinal pigment epithelium (RPE) and became more visible after week nine probably due to RPE degeneration. Loss of choriocapillaris was visualized at week 18. In control rats, no vascular change was detected, but nuclear layers, photoreceptor layers and total retina showed slight thinning with age ( P < 0.001). Conclusions Photoreceptor degeneration in RCS rats was associated with the loss of capillaries in DCP, but not in SVP. The OCTA imaging allows for the characterization of structural and angiographic changes in rodent models.