Majdi Joseph A, Qian Haohua, Li Yichao, Langsner Robert J, Shea Katherine I, Agrawal Anant, Hammer Daniel X, Hanig Joseph P, Cohen Ethan D
Division of Biomedical Physics, Office of Science and Engineering Labs, Center for Devices and Radiological Health, Food and Drug Administration, White Oak Federal Research Labs, Silver Spring, Maryland, United States.
National Eye Institute, Visual Function Core, National Institutes of Health, Bethesda, Maryland, United States.
Invest Ophthalmol Vis Sci. 2014 Dec 18;56(1):587-97. doi: 10.1167/iovs.14-15594.
We developed a novel technique for accelerated drug screening and retinotoxin characterization using time-lapse optical coherence tomography (OCT) and a drug microapplication device.
Using an ex vivo rabbit eyecup preparation, we studied retinotoxin effects in real-time by microperfusing small retinal areas under a transparent fluoropolymer tube. Known retinotoxic agents were applied to the retina for 5-minute periods, while changes in retinal structure, thickness, and reflectance were monitored with OCT. The OCT images of two agents with dissimilar mechanisms, cyanide and kainic acid, were compared to their structural changes seen histologically.
We found the actions of retinotoxic agents tested could be classified broadly into two distinct types: (1) agents that induce neuronal depolarization, such as kainic acid, causing increases in OCT reflectivity or thickness of the inner plexiform and nuclear layers, and decreased reflectivity of the outer retina; and (2) agents that disrupt mitochondrial function, such as cyanide, causing outer retinal structural changes as evidenced by a reduction in the OCT reflectivity of the photoreceptor outer segment and pigment epithelium layers.
Retinotoxin-induced changes in retinal layer reflectivity and thickness under the microperfusion tube in OCT images closely matched the histological evidence of retinal injury. Time-lapse OCT imaging of the microperfused local retina has the potential to accelerate drug retinotoxicological screening and expand the use of OCT as an evaluation tool for preclinical animal testing.
我们开发了一种新技术，利用延时光学相干断层扫描（OCT）和药物微量应用装置进行加速药物筛选和视网膜毒素特性分析。
使用离体兔眼杯制备物，我们通过在透明含氟聚合物管下对小面积视网膜进行微量灌注来实时研究视网膜毒素的作用。将已知的视网膜毒性剂应用于视网膜5分钟，同时用OCT监测视网膜结构、厚度和反射率的变化。将两种作用机制不同的药剂（氰化物和 kainic 酸）的OCT图像与其组织学观察到的结构变化进行比较。
我们发现所测试的视网膜毒性剂的作用可大致分为两种不同类型：（1）诱导神经元去极化的药剂，如 kainic 酸，导致OCT反射率增加或内网状层和核层厚度增加，以及外视网膜反射率降低；（2）破坏线粒体功能的药剂，如氰化物，导致外视网膜结构变化，表现为光感受器外段和色素上皮层的OCT反射率降低。
OCT图像中微量灌注管下视网膜毒素诱导的视网膜层反射率和厚度变化与视网膜损伤的组织学证据密切匹配。对微量灌注的局部视网膜进行延时OCT成像有潜力加速药物视网膜毒理学筛选，并扩大OCT作为临床前动物试验评估工具的应用。
