Abstract
Purpose: :
To assess the retinal toxicity of varying concentrations of intravitreally administered fludrocortisone acetate micronized, a synthetic steroid with a high level of glucocorticoid activity.
Methods: :
Twenty–five New Zealand albino rabbits were used for this study and divided in five groups. The animals were treated in accordance with the ARVO guidelines on the care and use of animals in research. The initial concentration of fludrocortisone (1 mg/ml) was titrated using sterile balanced saline solution (BSS) to the following concentrations: 4 mg/0.1 ml, 2 mg/0.1 ml, 1 mg/0.1 ml, and 400 µg/0.1 ml, which were injected intravitreally into one eye of each animal per group. The control eyes received 0.1 ml of sterile BSS. All animals were examined before and after injection using the indirect ophthalmoscope and slit–lamp biomicroscopy. Electroretinography (ERG) was performed on all animals before intravitreal injection and two weeks after injection. The animals were re–examined at this time by indirect ophthalmoscopy and slit–lamp biomicroscopy and were euthanized. The eyes were enucleated and examined with light microscopy.
Results: :
Two eyes in the 4 mg/0.1 ml fludrocortisone group exhibited significant decreases in ERG; one eye of this group had an intravitreal hemorrhage. There was no significant decrease in ERG in the other groups. There were no signs of retinal toxicity on slit–lamp examination, indirect ophthalmoscopy, or by light microscopy in all eyes injected with 4 mg/0.1 ml or less of fludrocortisone.
Conclusions: :
Intravitreal injections of fludrocortisone at 2 mg/0.1 ml appeared safe in the albino rabbit eye. Fludrocortisone should be investigated for the treatment of various retinal vascular inflammatory diseases.
Keywords: drug toxicity/drug effects • inflammation