Abstract
Purpose: :
Raptiva is an immunosuppressant, designed to selectively and reversibly block the activation, reactivation and trafficking of T-cells. The purpose of this study is to evaluate the retinal toxicity of two doses of raptiva when injected intravitreally in rabbits.
Methods: :
Ten male pigmented rabbits (divided into two groups, five animals per group) were used for this study. Two concentrations of efalizumab were tested: 12.5mg/0.1mL and 0.125mg/0.1mL. Each concentration was injected intravitreally randomly in one eye (study group) of each rabbit (group 1 received 12.5mg/0,1ml and group 2 received 0.125mg/0,1ml), while in the other eye (control group) 0.1mL of sterile balanced saline solution (BSS) was injected. Slit lamp and funduscopic examinations were performed every second day for 2 weeks for signs of infection, inflammation and toxicity. A baseline electroretinogram (ERG) was performed before the experiment and at the last follow up day (day 14). ERG examination followed ISCEV standards. At the last follow up day, the animals were sacrificed and the enucleated eyes were prepared for histological evaluation of retinal toxicity.
Results: :
No signs of retinal detachment, media opacity, inflammation, vitreous hemmorrhage or optic atrophy were noticed during the 14 days follow-up (clinical observations) in all eyes. Differences in ERG responses at photopic and scotopic conditions were observed in the group 1 study eyes, while no differences were observed in the group 2 study eyes. Finally, histologic examination of the retina in the enucleated eyes demonstrated signs of retinal toxicity for group 1 (study eyes), while normal retinal histology was demonstrated for group 2 (study eyes).
Conclusions: :
Intravitreal efalizumab appeared toxic to the retina in this experimental model at a concentration of 12.5mg (100 times larger than the systemic equivalent administration), while the 0.125mg dose did not apper toxic. Intravitreal injection of efalizumab could be evaluated for the possible treatment of a variety of intraocular inflammatory conditions.
Keywords: electrophysiology: non-clinical • retina