Ocular Safety of Intravitreal Ethylene Diamine Tetra Acetic Acid (EDTA)
Khalil Ghasemi Falavarjani1 *
- Eye Research Center, The Five Senses Institute, Rassoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran.
Abstract: To determine the safe dose of intravitreal ethylene diamine tetra acetic acid (EDTA), an antioxidative and potential neuroprotective drug, in rabbit eyes.
Methods: Ten New Zealand albino rabbits were categorized into five groups; right eyes of the animals in each group received intravitreal injection of one of the dilutions of EDTA (112.5, 225, 450, 900 and 1800 µg /0.1 mL). Fellow eyes received either intravitreal injection of 5% dextrose water (5 eyes) or no injection (5 eyes). In addition to slit-lamp biomicroscopy and indirect ophthalmoscopy, electroretinography (ERG) was performed at the baseline and day 28, when all animals were euthanized. The enucleated eyes were subjected to histopathological study for hematoxylin and eosin staining, immunohistochemistry for glial fibrillary acidic protein (GFAP) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) test.
Results: During the follow up visits at days 1, 3, 7, 14 and 28 after the injection, no sign of media opacity, inflammation or infection was detected in any eyes by slit-lamp biomicroscopy and indirect ophthalmoscopy. Also, hematoxylin and eosin staining and TUNEL assay were unremarkable for any pathologic findings. Based on ERG test, eyes with an intravitreal injection dosage of 112.5 µg EDTA did not have any significant change compared to the baseline values in all responses. A significant decrease in at least one of the a- or b-wave measurements of responses was found in higher dosages (> 112.5 µg) of EDTA. The mean scores of GFAP immune reactivity in the eyes injected with 112.5 and 225 µg EDTA showed a non-significant reaction. The mean GFAP scores in higher doses were significant.
Conclusion: This study suggests that EDTA with the concentration of 112.5 µg may be safe for intravitreal injection in rabbits. Confirmation of the safe dose and contribution of intravitreal EDTA in neuroprotection requires further studies.
