Pathology of damaging electrical stimulation in the retina
Pathology of damaging electrical stimulation in the retina
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DOI：
10.1016/j.exer.2007.02.014
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发表时间：
2007-07-01
影响因子：
3.4
通讯作者：
Humayun, M. S.
中科院分区：
文献类型：
--
作者：
Colodetti, L.;Weiland, J. D.;Humayun, M. S.
本研究的目的是研究电致视网膜损伤的特征。视网膜假体必须既有效又安全，但大多数与视网膜电刺激有关的研究都涉及到有效性的测量（例如，刺激阈值），而相对较少的研究调查了电刺激的安全性。在本研究中，将单个铂微电极插入正常视力的成年朗埃文斯色素大鼠的玻璃体腔内。其中一组动物电极与视网膜不接触，施加0.05 （n = 3）和0.2 (n = 6) μ C/相的电流脉冲。在第二组中，电极与视网膜之间有明显接触（视网膜有轻微凹陷），并施加0.09 (n - 4) μ C/相的电流脉冲。在这两种情况下，刺激脉冲（双相，阴极第一，1 ms/相）在100 Hz下施加1小时。同时，对照实验进行无视网膜接触电刺激（n = 4）和无视网膜接触（n = 3）。刺激后，动物存活2周，眼部摄影和视网膜电图（ERG）记录变化。在随访期间，只有当电极接触视网膜时，无论有无电刺激，都观察到视网膜的变化。测试眼和受刺激眼在电刺激振幅和潜伏期上没有差异。2周牺牲后进行组织学分析。建立了一种半定量的方法对视网膜/RPE/脉络膜外观的18个特征进行评分，并对测试眼和对照眼进行整数评分。采用该方法并比较受影响最严重的区域（最高等级），除内核层厚度外，视网膜接触实验与非视网膜接触实验在所有特征上均有显著差异（p < 0.05）。根据电的强度，在一组内没有发现差异；刺激应用。视网膜接触和电刺激的受影响区域的大小明显大于单独接触视网膜。我们得出的结论是，单独的机械压力和机械压力加上过度的电刺激会导致视网膜损伤，但电刺激加上机械压力会增加损伤的面积。(c) 2007 Elsevier Ltd.版权所有。
The goal of this study was to examine the characteristics of electrically induced retinal damage. A retinal prosthesis must be both effective and safe, but most research related to electrical stimulation of the retina has involved measures of efficacy (for example, stimulus threshold), while relatively little research has investigated the safety of electrical stimulation. In this study, a single platinum microelectrode was inserted into the vitreous cavity of normally-sighted adult Long Evans pigmented rats. In one group of animals, no contact was made between the electrode and he retina and current pulses of 0.05 (n = 3) and 0.2 (n = 6) mu C/phase were applied. In a second group, visible contact (slight dimpling of the retina) was made between the electrode and the retina and current pulses of 0.09 (n - 4) mu C/phase were applied. In both cases, stimulus pulses (biphasic, cathodic first, 1 ms/phase) were applied for 1 h at 100 Hz. Also, control experiments were run with no electrical stimulation with retina contact (n = 4) and with no retinal contact (n = 3). After stimulation, the animal was survived for 2 weeks with ocular photography and electroretinography (ERG) to document changes. During the follow-up period, retinal changes were observed only when the electrode contacted the retina, with or without electrical stimulation. No difference was noted in ERG amplitude or latency comparing the test eye to the stimulated eye. Histological analysis was performed after sacrifice at 2 weeks. A semi-quantitative method for grading 18 features of retina/RPE/choroidal appearance was established and integer grades applied to both test and control eyes. Using this method and comparing the most severely affected area (highest grade), significant differences (p < 0.05) were noted between experiments with retinal contact and without retinal contact in all features except inner nuclear layer thickness. No difference was noted within a group based on the intensity of electrical;stimulus applied. The size of the affected area was significantly larger with both retinal contact and electrical stimulation compared to with retinal contact alone. We conclude that mechanical pressure alone and mechanical pressure with excessive electrical stimulation causes damage to the retina but that electrical stimulation coupled with mechanical pressure increases the area of the damage. (c) 2007 Elsevier Ltd. All rights reserved.