Long-term Characterization of Retinal Degeneration in Royal College of Surgeons Rats Using Spectral-Domain Optical...

Area of Science:

• Ophthalmology
• Retinal imaging
• Animal models

Background:

• Age-related macular degeneration and inherited retinal degenerations are significant causes of vision loss.
• The Royal College of Surgeons (RCS) rat is a key preclinical model for evaluating prospective treatments.
• Traditional postmortem retinal thickness measurements limit longitudinal study designs.

Purpose of the Study:

• To establish a baseline for longitudinal retinal thickness quantification in RCS rats using spectral-domain optical coherence tomography (SD-OCT).
• To enable non-invasive, serial assessment of retinal changes in a model of retinal degeneration.

Main Methods:

• SD-OCT scans were performed on Long-Evans control rats and RCS rats at various ages (P17-P90).
• Quantification of total retina (TR), outer nuclear layer+ (ONL+), inner nuclear layer (INL), and retinal pigment epithelium (RPE) thicknesses.
• Histological comparison of RCS retinal sections with SD-OCT images.

Main Results:

• RCS rats showed significant decreases in TR and ONL+ thickness compared to controls.
• A subretinal hyperreflective layer (HRL), identified as disorganized outer segments and debris, was observed and quantified in RCS rats from P30 to P90.
• INL and RPE thickness did not differ significantly between groups.

Conclusions:

• SD-OCT provides reliable longitudinal quantification of retinal layer thickness in the RCS rat model.
• Measurements are consistent with historical anatomic assessments.
• This study establishes crucial baseline data for future therapeutic evaluations in preclinical models of retinal degeneration.