title: Efficacy of suprachoroidal-transretinal stimulation in a rabbit model of retinal degeneration.
abstract: Purpose. To develop a middle-sized animal model of outer retinal degeneration and to evaluate the effectiveness of suprachoroidal-transretinal stimulation (STS) in eliciting cortical potentials from this model. Methods. Twelve rabbits were intravenously injected with 0.47 mg/kg verteporfin and the retinas were irradiated with a red light for 90 minutes. Fluorescein angiography and full-field and focal electroretinography (ERG) were performed at 7 and 28 days after the irradiation. Electrically evoked potentials (EEPs) were elicited by electrical stimulation, with the STS electrode implanted over the irradiated region, 1 month and 1 year after the irradiation. EEPs were also recorded from three rabbits before and after retinotomy of the normal retina surrounding the degenerated area, to eliminate the influence of stray currents. The retina beneath the site of the STS electrode was examined histologically at 1 month (group 1) and 1 year (group 2) after the irradiation. Results. An extensive area of degeneration was detected histologically, mainly in the outer retina after the irradiation. Focal ERGs were not recorded when the stimulus was confined to the irradiated area; however, EEPs were successfully elicited by STS of the same area 1 month and 1 year after the irradiation. The 360 degrees retinectomy did not significantly alter the amplitudes, the implicit times, or the thresholds of EEPs evoked by STS. Conclusions. Verteporfin with light irradiation induces degeneration predominantly in the outer retinal layers in rabbits. The elicitation of EEPs by STS from the degenerated area suggests that the STS system may be useful in patients with retinitis pigmentosa.
authors.affiliation: Department of Ophthalmology, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Nishida
authors.forename: Motohiro
authors.initials: M
authors.lastname: Kamei
authors.forename: Mineo
authors.initials: M
authors.lastname: Kondo
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Sakaguchi
authors.forename: Mihoko
authors.initials: M
authors.lastname: Suzuki
authors.forename: Takashi
authors.initials: T
authors.lastname: Fujikado
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Tano
mesh_terms: D000818:Animals; D002829:Choroid / Q000502:physiology*; D004195:Disease Models, Animal; D004558:Electric Stimulation; D004567:Electrodes, Implanted; D004596:Electroretinography; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005451:Fluorescein Angiography; D008027:Light; D010775:Photic Stimulation; D010778:Photochemotherapy / Q000009:adverse effects; D017319:Photosensitizing Agents / Q000633:toxicity; D011166:Porphyrins / Q000633:toxicity; D011817:Rabbits; D012160:Retina / Q000502:physiology*; D012162:Retinal Degeneration / Q000139:chemically induced / Q000503:physiopathology*; D000077362:Verteporfin
chemical_list: D017319:Photosensitizing Agents; D011166:Porphyrins; D000077362:Verteporfin