Abstract
Purpose: :
To determine the morphologic effects of intravitreal acyclovir on the rabbit retina and the maximum non-toxic dose to the retina.
Methods: :
Acyclovir (Acyclovir®, Bedford Laboratories, Bedford, OH) was injected in the vitreous of 51 Dutch Belted rabbits in five concentrations (0.1, 0.5, 1, 5, and 10 mg/0.1 ml). As control, the contralateral eye of each rabbit was injected with saline. Animals were periodically examined and photographed. They were sacrificed at different time points (1, 7, and 14 days, and 1 month) and inferior retina was analyzed by light and transmission electron microscopy.
Results: :
Eyes injected with 10 mg of acyclovir showed complete destruction of external and internal photoreceptor segments, and disorganization of photoreceptors. Eyes injected with 5 mg of acyclovir showed outer segment disorganization. Eyes injected with 1 mg or less did not show any morphologic change on light microscopy, similar to eyes injected with saline. Two eyes, injected with 1 and 0.5 mg, were processed for electron microscopy and did not show any morphologic change.
Conclusions: :
Intravitreal injections of 5 and 10 mg of acyclovir produce morphologic changes in rabbit retina, while injections of 1 mg or less seem to be safe. These data suggest that intravitreal injection of acyclovir is a potential treatment for the devasting herpetic retinitis. However more studies should be carried before it is used in clinical practice.
Keywords: antiviral drugs • retina