title: Long-term Characterization of Retinal Degeneration in Royal College of Surgeons Rats Using Spectral-Domain Optical Coherence Tomography.
abstract: Prospective treatments for age-related macular degeneration and inherited retinal degenerations are commonly evaluated in the Royal College of Surgeons (RCS) rat before translation into clinical application. Historically, retinal thickness obtained through postmortem anatomic assessments has been a key outcome measure; however, utility of this measurement is limited because it precludes the ability to perform longitudinal studies. To overcome this limitation, the present study was designed to provide a baseline longitudinal quantification of retinal thickness in the RCS rat by using spectral-domain optical coherence tomography (SD-OCT).
  
  
  
  Horizontal and vertical linear SD-OCT scans centered on the optic nerve were captured from Long-Evans control rats at P30, P60, P90 and from RCS rats between P17 and P90. Total retina (TR), outer nuclear layer+ (ONL+), inner nuclear layer (INL), and retinal pigment epithelium (RPE) thicknesses were quantified. Histologic sections of RCS retina obtained from P21 to P60 were compared to SD-OCT images.
  
  
  
  In RCS rats, TR and ONL+ thickness decreased significantly as compared to Long-Evans controls. Changes in INL and RPE thickness were not significantly different between control and RCS retinas. From P30 to P90 a subretinal hyperreflective layer (HRL) was observed and quantified in RCS rats. After correlation with histology, the HRL was identified as disorganized outer segments and the location of accumulated debris.
  
  
  
  Retinal layer thickness can be quantified longitudinally throughout the course of retinal degeneration in the RCS rat by using SD-OCT. Thickness measurements obtained with SD-OCT were consistent with previous anatomic thickness assessments. This study provides baseline data for future longitudinal assessment of therapeutic agents in the RCS rat.
authors.affiliation: Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States.
authors.forename: Renee C
authors.initials: RC
authors.lastname: Ryals
authors.affiliation: Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Andrews
authors.affiliation: Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States.
authors.forename: Shreya
authors.initials: S
authors.lastname: Datta
authors.affiliation: Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States.
authors.forename: Aaron S
authors.initials: AS
authors.lastname: Coyner
authors.affiliation: Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States.
authors.forename: Cody M
authors.initials: CM
authors.lastname: Fischer
authors.affiliation: Baylor University Medical Center, Dallas, Texas, United States.
authors.forename: Yuquan
authors.initials: Y
authors.lastname: Wen
authors.affiliation: Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Pennesi
authors.affiliation: Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States 3Department of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon, United States.
authors.forename: Trevor J
authors.initials: TJ
authors.lastname: McGill
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005500:Follow-Up Studies; D011446:Prospective Studies; D051381:Rats; D020318:Rats, Long-Evans; D015203:Reproducibility of Results; D012162:Retinal Degeneration / Q000473:pathology*; D055213:Retinal Pigment Epithelium / Q000473:pathology*; D013997:Time Factors; D041623:Tomography, Optical Coherence / Q000379:methods*