Decreased Visual Function after Patchy Loss of Retinal Pigment Epithelium Induced by Low-Dose Sodium Iodate

• Published in: Investigative ophthalmology & visual science Vol. 50; no. 8; pp. 4004 - 4010
• Main Authors: Franco, Luisa M, Zulliger, Rahel, Wolf-Schnurrbusch, Ute E. K, Katagiri, Yoshiaki, Kaplan, Henry J, Wolf, Sebastian, Enzmann, Volker
• Format: Journal Article
• Language: English
• Published: Rockville, MD ARVO 01-08-2009; Association for Research in Vision and Ophtalmology
• Subjects: Animals; Behavior, Animal; Biological and medical sciences; Eye and associated structures. Visual pathways and centers. Vision; Fundamental and applied biological sciences. Psychology; Injections, Intravenous; Iodates - administration & dosage; Iodates - toxicity; Male; Maze Learning; Medical sciences; Mice; Mice, Inbred C57BL; Nystagmus, Optokinetic; Ophthalmology; Psychomotor Performance - drug effects; Retinal Diseases - chemically induced; Retinal Diseases - physiopathology; Retinal Pigment Epithelium - drug effects; Retinal Pigment Epithelium - pathology; Vertebrates: nervous system and sense organs; Vision disorders; Vision Disorders - chemically induced; Vision Disorders - physiopathology; Visual Acuity - drug effects; Visual Acuity - physiology; Eye disease; Sodium; Visual impairment; Vision disorder; Low dose; Blindness; Pigment epithelium; Retina; Ophthalmology
• ISSN: 0146-0404; 1552-5783; 1552-5783
• DOI: 10.1167/iovs.08-2898

To correlate damage to the retinal pigment epithelium (RPE) with decreased visual function after the systemic administration of sodium iodate (NaIO(3)).
Damage was produced in mice by injection of 15, 25, or 35 mg/kg NaIO(3). Visual function was assessed with the cued water maze (WM) behavioral test and the optokinetic reflex (OKR) measurement at different times after injection. Autofluorescence in whole eye flatmounts was quantified, and hematoxylin and eosin staining of paraffin sections was performed to assess changes in the outer retina.
After 15 mg/kg NaIO(3), cued WM test results were normal, whereas OKR measurements were significantly decreased at all times. Focal RPE loss began on day 21, but no significant damage to the outer nuclear layer was observed. After 25 mg/kg NaIO(3), the cued WM test was transitionally reduced and the OKR measurement again decreased at all times. Large areas of RPE loss occurred on day 14 with a reduced outer nuclear layer on the same day. With 35 mg/kg NaIO(3), the cued WM test was reduced beginning on day 14 with complete obliteration of the OKR beginning on day 3, large areas of RPE loss on the same day, and a reduced outer nuclear layer on day 7.
Stable, patchy RPE loss was observed with a low concentration of NaIO(3). The OKR measurement showed changes in visual function earlier than the cued WM test and before histologic findings were observed.