AIM: To characterize the effects of sodium iodate on mouse retinal morphology and function.

METHODS: Sodium iodate at 35mg/kg(body weight)was administered by tail vein injection into adult 6-8wk C57BL/6J mice. Morphological and functional changes of the retina were assessed at 6h, 1, 3, 5 and 8d after injections by fundus imaging, optical coherence tomography(OCT), ERG and histology. Mice in control group were give tail vein injection of equivalent dose of normal saline. All the eyeballs were removed for paraffin section and H-E staining.

RESULTS: The fundus photographs images at 6h after injection showed obvious changes, which were light red in retina and showed retinal blood vessels radial arranged. At 6h after injection, off-white drusen-like change was found at fundus. While there were no observable changes in OCT image and ERG. At 1d after injection, the fundus lesion aggravated and the drusen increased gradually. There were retinal pigment epithelial(RPE)disorders, photoreceptors and outer nuclear layer(ONL)damage through OCT. At 3d after injection, the retina lesion aggravated further and the retina became edema. At 5d after injection, the retina edema cleared away, the optic nerve became white and the fundus lesions increased. At 8d after injection, the RPE layer, photoreceptors and ONL were destroyed obviously. In the process, ERG showed the amplitudes of a- and b-wave decreased in a time-dependent manner. H-E staining showed that cells in retina of mice in control group were neatly arranged and well-distributed. The outer layer retina of sodium iodate injection group was wave-like, the normal structure of RPE disappeared and black round sediment could be seen which increased with time. At 8d after injection, there were any normal RPE.

CONCLUSION: The tail vein injection of sodium iodate can well simulate the pathogenesis of age-related macular degeneration which can provide a good animal model for AMD.