Abstract
Purpose::
We are developing a unique retinal prosthesis with suprachoroidal-transretinal stimulation (STS) and require a middle-sized animal model of retinal degeneration for functional evaluation. There is no appropriate animal model of selective injury in the outer retinal layer observed in the cases of retinitis pigmentosa or late phase age-related macular degeneration with a simple device. We, therefore, try to establish a rabbit model with selective degeneration of the outer retinal layer.
Methods::
Pigmented rabbits(weight 2.0-2.3kg)were exposed to a blue light emitting diode (LED) light (illuminance: 9.5mW/cm2, transmission peak wavelength: 480 nm) continuously for 8 hours (n=3) and 24 hours (n=3). Ophthalmological examinations including fundus photograph, fluorescein angiogram (FA), and electroretinogram (ERGs) were performed before and at various time points after irradiation. The animals were euthanasized at different periods after irradiation including 0, 5 and 15 days, and the eyes were enucleated and prepared for HE staining and histological evaluation.
Results::
White lesions were observed in the visual streak after 8hours’ exposure, which showed hyper fluorescence in FA. There was no apparent change in ERGs. Histologically, a marked disruption of outer nuclear layer and photoreceptor layer were observed after 24-hour exposure, while the retinas with 8-hour exposure showed no apparent histological change. The histologically damaged lesion was a round localized area of the white area observed in visual streak.
Conclusions::
Long-term exposure (more than 8 hours ) of blue light selectively damaged the outer retinal layer. Since the degeneration size is not enough for a retinal degeneration model, further investigation is needed to enlarge the degenerated lesions to the entire retina.
Keywords: retinal degenerations: cell biology • photoreceptors • retina