Electrophysiological evaluation of injection of tissue plasminogen activator into optic nerve

Abstract

Background Retinal vein occlusion (RVO) is a common vasculoretinopathy in ophthalmology.No an effective treating way is confirmed so far,and some new approach is in exploration.Objective The present study aims to investigate the safety and feasibility of injection of tissue plasminogen activator into optic nerve for the treatment of RVO using flash visual evoked potential (F-VEP) and flash electroretinogram(F-ERG).Methods The recording electrodes for F-VEP were implanted into the skull of rabbits to investigate the safety and feasibility of injection of tPA into the optic nerve.25μg of tPA or 12.5μg tPA (0.1 mL) was injected in pars plane via the center of optical disc respectively in different groups (6 eyes in each group),and 0.1 mL of BSS was injected at the same method in control group.Other 6 eyes were as normal control group.Slit lamp biomicroscope,indirect ophthalmoscope,F-VEP and F-ERG examinations were performed in 1 day,3,4,14 and 28 days after injection.All experiments were conducted in accordance with the Association for Research in Vision and Ophthalmology statement on the use of animals in ophthalmic and Vision Research.Results No obvious evidence of optic nerve or retinal toxicity or damage was found by the examination of ophthalmoscope,F-VEP,and F-ERG after injection of tPA.No significantly differences were found in the mean latency of P_1 wave of F-VEP (P=0.411),the mean amplitude of P_1 wave of F-VEP (P=0.065),the mean latency and amplitude of ERG a-waves (P=0.627,P=0.725) as well as the mean latency and amplitude of ERG b-waves (P=0.257,P=0.096) among 25 μg of tPA group,12.5 μg tPA group,BSS group and control group.Conclusion The injection of tPA into optic nerve is a safe and simple procedure.This therapy may is a potential approach to the treatment of RVO. Key words: tissue plasminogen activator; optic disc; retinal vein occlusion