In Vivo Sampling to Study the Neurobiology of Glaucoma

描述(申请人提供)：青光眼是一种神经退行性疾病，是世界上导致失明的主要原因。虽然目前的治疗目标是降低眼压(LOP)，但即使LOP降低，神经变性有时也会继续。谷氨酸介导的兴奋性毒性可能是导致视网膜神经节细胞选择性破坏的机制之一。不幸的是，目前测量眼睛组织中谷氨酸的方法并不能提供所有所需的空间分辨率来表征视网膜谷氨酸水平及其潜在来源。这项建议的目标是开发和展示一种新的活体采样系统，该系统为表征青光眼大鼠模型的玻璃体谷氨酸水平提供所需的空间定位。在这个项目的第一阶段，我们实验室开发的一种微型、低流量推拉灌注法和一种合适的谷氨酸毛细管电泳法将被改装用于玻璃体。我们的低流量推拉灌流的空间分辨率将用于表征中央玻璃体和玻璃体-视网膜界面处的谷氨酸水平。此外，探针尖端谷氨酸水平的来源和动态将通过在灌注液中加入药理试剂来评估。在这个项目的第二阶段，取样方法将被用来解决这样的假设，即在青光眼大鼠模型中，随着LOP的慢性、适度增加，视网膜特定位置的谷氨酸水平会增加。在LOP适度增加的前两周，将在视网膜的中央和外围位置进行玻璃体视网膜谷氨酸水平的测量。该项目的成果将是引入一种在眼组织中进行活体采样的新工具，并将提供以前无法获得的关于青光眼视网膜谷氨酸的神经生物学的信息。此外，这项研究中展示的表征视网膜化学成分的能力可能适用于对其他视网膜疾病的创新研究。

DESCRIPTION (provided by applicant): Glaucoma is a neurodegenerative disorder that is the leading cause of blindness in the world. While current treatments are aimed toward reducing the intraocular pressure (lOP), neurodegeneration sometimes continues even with a reduction in lOP. One of the mechanisms that may lead to the selective destruction of retinal ganglion cells is a glutamate-mediated excitotoxicity. Unfortunately, current methods for measuring glutamate in eye tissues do not provide all The desired spatial resolution for characterizing retinal glutamate levels and their potential sources. The goal of this proposal is to develop and demonstrate a novel, in vivo sampling system that provides the needed spatial localization for characterizing vitreal glutamate levels in a rat model of glaucoma. In the first phase of this project, a miniaturized, low-flow push-pull perfusion method and an appropriate capillary electrophoresis assay for glutamate that have been developed in our lab will be adapted for use in the vitreous. The spatial resolution of our low-flow push-pull perfusion will be used to characterize glutamate levels at sites in the central vitreous and vitreoretinal interface. Additionally, the source and dynamics of glutamate levels at the probe tip will be assessed by the inclusion of pharmacological agents into the perfusion solution. In the second phase of this project, the sampling method will be used to address the hypothesis that glutamate levels increase in specific locations at the retina in response to a chronic, moderate increase in lOP in a rat model of glaucoma. Measurements of vitreoretinal glutamate levels will be performed at central and peripheral sites of the retina during the first two weeks of a moderate increase in lOP. The outcomes of this project will be the introduction of a new tool for in vivo sampling in eye tissues and will provide previously inaccessible information regarding the neurobiology of glutamate at the glaucomatous retina. Further, the ability to characterize chemical composition at the retina demonstrated in this study may be applicable to innovative studies of other diseases of the retina.