兔眼脉络膜上腔多通道微电极阵列植入后视网膜电刺激阈值的研究  

Threshold of electrical evoked potentials stimulated by a suprachoroidal multichannel electrode array in rabbit eyes

作　　者：刘广峰[1] 于伟泓[1] 郑霖[1] 杨志坤[1] 董方田[1] 王任鑫[2] 王玮[2] 李志宏[2] 

机构地区：[1]中国医学科学院北京协和医学院北京协和医院眼科,北京100730 [2]北京大学微电子学研究院,100871

出　　处：《眼科研究》2010年第5期395-399,共5页Chinese Ophthalmic Research

基　　金：国家高新技术研究发展计划项目(863计划)(2006AA04Z352)

摘　　要：目的研究兔眼脉络膜上腔多通道微电极阵列芯片植入术后,电刺激视网膜诱发的中枢电诱发电位(EEP)的阈值。方法将多通道刺激电极(二氯代环二聚体为基底,铂电极)植入9只青紫蓝兔左眼后极部的脉络膜上腔,将铂丝制成的参比电极置于玻璃体腔,硬膜外放置记录电极。刺激电极采用双向刺激的方式发出电刺激,在中枢记录EEP。测量产生EEP的阈值,连续记录30次取其平均值。实验结束后处死动物取出眼球行组织学检查。应用检眼镜和OCT检查评价多通道微电极阵列芯片植入和清除后对兔眼组织的安全性。结果多通道微电极阵列芯片成功植入9只实验兔眼的脉络膜上腔。当脉络膜上腔刺激电极发出电刺激后,可以在硬脑膜外的记录电极处记录到EEP,阈值为(107.14±17.14)nC,(68.20±10.91)μC/cm。光学显微镜下显示视网膜结构完整,刺激电极附近无明显的组织结构的破坏。检眼镜及OCT检查显示相应的脉络膜组织与邻近组织间连接紧密。结论置于脉络膜上腔的电极发出的电刺激可以有效地诱发出EEP,且其阈值较低;脉络膜上腔是较理想的视网膜假体放置部位。Background The implantation of visual prosthesis is a new approach to treat retinal degeneration. The threshold value of a microelectrode array is associated with the evoked potential value. Objective The aim of this study is to investigate the threshold electrical charge density of the retina in rabbits for the generation of electrical evoked potentials （EEP） by delivering electrical stimulation with a mieroetectrode array（MEA） implanted into the suprachoroidal space. Methods A flat electrode array（parylene C plate,platinum electrode） was developed and applied in this study. The left eyes of 9 chinchilla rabbits were selected as experimental eyes. After performing a scleral incision at 6 mm from the limbus,the array was inserted into the suprachoroidal space in the posterior portion of the eye. A platinum wire was implanted into the vitreous space as a reference electrode. For electrical stimulation, a biphasie pulse was used. When the electrode was stimulated, the EEP was recorded. The retinal threshold for generation of an EEP was determined for each MEA placement by consisting of 30 computer-averaged recordings. Animals were sacrificed at the conclusion of the experiment and the eyes were enueleated. The safety of this device to eye tissue was evaluated by ophthalmoscope,OCT and histological examination. Results The MEA was successfully implanted into the retina and suprachoroidal space. When the electrical stimulation from the superchoroidal space was applied,the EEP could he reeorded with an epidural electrode, and the threshold was 107. 14 ± 17. 14 nC （68.20 ± 10.91 μC/cm）. Histological examination indicated the absence of major damage to the retina and ehoroid from the insertion and placement of the array and the electrical stimulation. OCT revealed that the device attached to choriod and adjacent tissue. Conclusion Transretinal electrical stimulation from the supraehoroidal space could elicit EEP, suggesting that this approach may be useful for a retinal prosthesis system.

关 键 词：视觉假体 微电极阵列 脉络膜上腔电极 电诱发电位 阈值 

分 类 号：R774[医药卫生—眼科]