Morphological damage in rabbit retina caused by subretinal injection of indocyanine green.
OBJECTIVE
To investigate the effects of subretinal indocyanine green (ICG) on retinal morphology in rabbit eyes.


METHODS
Retinal bleb detachments were produced by injections of ICG at dosages of 25 mg/ml, 5 mg/ml, and 0.5 mg/ml or with an injection of balanced salt solution (BSS) into the subretinal space of albino rabbit eyes. Morphological change was assessed by light and transmission electron microscopy from the viewpoint of dose and time. Some sections were also probed with the TUNEL technique to detect apoptotic cells.


RESULTS
At 14 days after subretinal injection of BSS and 0.5 mg/ml ICG, the structure of the retina was well preserved. However, injections of 5 mg/ml or 25 mg/ml caused thinning of the retina, especially loss of the outer retinal layer. In eyes injected with 5 mg/ml ICG, the photoreceptors began disappearing within 3 days after the injection and over time showed the development of retinal atrophy. TUNEL-positive cells appeared abundantly in the photoreceptor layers 1 and 3 days after the injection of 5 mg/ml ICG. Transmission electron microscopy confirmed apoptosis in the photoreceptors.


CONCLUSIONS
These data indicate that subretinal ICG induces apparent morphological damage of the retina in a dose-dependent manner.
Kawaji
Takahiro
T
Department of Ophthalmology and Visual Science, Kumamoto University Graduate School of Medical Sciences, Honjo 1-1-1, 860-8556, Kumamoto , Japan.
Hirata
Akira
A
Department of Ophthalmology and Visual Science, Kumamoto University Graduate School of Medical Sciences, Honjo 1-1-1, 860-8556, Kumamoto , Japan. ahirata@kumamoto-u.ac.jp.
Inomata
Yasuya
Y
Department of Ophthalmology and Visual Science, Kumamoto University Graduate School of Medical Sciences, Honjo 1-1-1, 860-8556, Kumamoto , Japan.
Koga
Takahisa
T
Department of Ophthalmology and Visual Science, Kumamoto University Graduate School of Medical Sciences, Honjo 1-1-1, 860-8556, Kumamoto , Japan.
Tanihara
Hidenobu
H
Department of Ophthalmology and Visual Science, Kumamoto University Graduate School of Medical Sciences, Honjo 1-1-1, 860-8556, Kumamoto , Japan.
D000818:Animals; D017209:Apoptosis; D001284:Atrophy; D004396:Coloring Agents / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D020287:In Situ Nick-End Labeling; D007208:Indocyanine Green / Q000633:toxicity*; D007267:Injections; D011817:Rabbits; D012160:Retina / Q000187:drug effects* / Q000648:ultrastructure; D012164:Retinal Diseases / Q000139:chemically induced* / Q000473:pathology
D004396:Coloring Agents; D007208:Indocyanine Green