title: Assessing sodium iodate-induced outer retinal changes in rats using confocal scanning laser ophthalmoscopy and optical coherence tomography.
abstract: OBJECTIVE
  Sodium iodate induces RPE atrophy and photoreceptor degeneration, as seen in the pathogenesis of many retinal diseases. We investigated a new approach of analyzing retinal images using confocal scanning laser ophthalmoscopy (cSLO) that allows longitudinal assessment of sodium iodate-induced lesions in the retina of living rats.
  
  
  METHODS
  A single dose of sodium iodate (25-75 mg/kg) was given intravenously to adult Sprague-Dawley rats. Control animals were given normal saline or sodium iodide. The retina was examined by cSLO and optical coherence tomography (OCT) in living rats, which were then killed for histologic assessments.
  
  
  RESULTS
  Confocal scanning laser ophthalmoscopy revealed the appearance of dark patchy blots in planar images of the retina 7 days after intravenous injection of sodium iodate (25-75 mg/kg). This finding coincided with the observations of degenerative changes in the outer retinal layers in OCT images and in histology of the retina. Further analyses showed a concomitant localization of degenerative profiles in histologic preparations of this retina, suggesting that the blots corresponded to the deteriorating photopigments and outer nuclear layer (ONL). In histologic sections, these degenerative profiles appeared as irregular folds or rosettes in the ONL. Quantitative analyses showed that the changes in blot number were dose dependent, which again coincided with results showing a dose-dependent lesion in the photopigment layer and ONL in histologic sections of the retina.
  
  
  CONCLUSIONS
  Sodium iodate-induced degenerative changes can be assessed quantitatively and reliably by in vivo retinal imaging using cSLO in adult rats, allowing efficient evaluation of lesions in a large area of retina in longitudinal studies.
authors: Department of Ophthalmology and Visual Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China.
authors: Yaping
authors: Y
authors: Yang
authors: Tsz Kin
authors: TK
authors: Ng
authors: Cong
authors: C
authors: Ye
authors: Yolanda W Y
authors: YW
authors: Yip
authors: Kasin
authors: K
authors: Law
authors: Sun-On
authors: SO
authors: Chan
authors: Chi Pui
authors: CP
authors: Pang
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D018450:Disease Progression; D007452:Iodates / Q000633:toxicity; D018613:Microscopy, Confocal / Q000379:methods; D009887:Ophthalmoscopy / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012162:Retinal Degeneration / Q000139:chemically induced / Q000473:pathology*; D055214:Retinal Photoreceptor Cell Outer Segment / Q000187:drug effects / Q000473:pathology*; D041623:Tomography, Optical Coherence / Q000379:methods*
chemical_list: D007452:Iodates; C032285:sodium iodate
keywords: histology; in vivo; retinal degeneration