Neural Stability after Retinal Detachment

项目总结/摘要 视网膜脱离手术后的视力恢复通常令人失望， 报告视力低于正常的患者。视网膜神经元经历戏剧性的结构可塑性后， 分离，包括杆轴突的回缩，锥体终末的变圆，以及双极和 水平细胞。在动物模型中，这些变化中的一些发生在视网膜损伤后数小时内。已经 表明这种突触重塑导致视力恢复不良。在视网膜细胞培养中， RhoA-Rho激酶（ROCK）信号级联的激活主要负责视杆细胞轴突 收回因此，本申请测试了RhoA拮抗剂和RhoA拮抗剂的联合疗法的假设。 视网膜手术可以通过预防视网膜脱离， 或降低突触可塑性。这一假设将在眼睛与人类相似的成年猪身上进行测试 1）检测RhoA拮抗剂是否能抑制其活性， RhoA、ROCK或其底物的结合将阻止由分离引起的结构突触变化 包括视杆轴突回缩、视杆-双极突触溶解、视锥终末形态学改变， 双极细胞出芽。还将检查对神经胶质细胞反应性的影响; 2）为了确定是否 RhoA相关药物可以在脱离后应用，这是一种更具治疗相关性的情况，如果是这样， 损伤后多久; 3）确定用RhoA相关药物治疗的视网膜脱落是否确实 有助于复位手术后视觉结构和功能的恢复。将通过以下方式评估形态学： 免疫组织化学、图像分析和共聚焦激光扫描和电子显微镜。水平 Rho信号传导的活性和时程将通过生物化学测定来确定， 这包括RhoA激活和肌球蛋白轻链磷酸化。视网膜功能 将通过视网膜电图评估再附着。将测试的一些药物（Ct-04和 法舒地尔）已经被批准用于人类使用。我们希望能确定大概的剂量， 如果RhoA拮抗剂被证明是外科手术的有用辅助， 再附着

Project Summary/Abstract Visual recovery after repair of a retinal detachment is often disappointing with more than half of treated patients reporting below normal visual acuity. Retinal neurons undergo dramatic structural plasticity after detachment including retraction of rod axons, rounding of cone terminals, and sprouting by bipolar and horizontal cells. Some of these changes occur within hours after retinal injury in animal models. It has been suggested that this synaptic remodeling contributes to poor visual recovery. In retinal cell cultures, activation of the RhoA-Rho kinase (ROCK) signaling cascade is primarily responsible for rod axon retraction. Thus, this application tests the hypothesis that a combined therapy of RhoA-antagonists and retinal surgery may significantly improve the visual outcome after repair of a detached retina by preventing or reducing synaptic plasticity. This hypothesis will be tested on adult pigs, whose eyes are similar to human eyes, focusing on the following specific aims: 1) To test whether RhoA antagonists which inhibit the activity of RhoA, ROCK, or their substrates will prevent the structural synaptic changes caused by detachment including rod axon retraction, rod-bipolar synaptic dissolution, cone terminal morphological change, and bipolar cell sprouting. The effect on glial cell reactivity will also be examined; 2) To determine whether RhoA-related drugs can be applied after a detachment, a more therapeutically relevant scenario, and if so, how long after the injury; and 3) To determine if detached retinas treated with RhoA-related drugs indeed help visual structural and functional recovery after reattachment surgery. Morphology will be assessed by immunohistochemistry, image analysis and confocal laser scanning and electron microscopy. Levels of activity and the time-course of Rho signaling will be determined by biochemical assays for multiple components including RhoA activation and myosin light chain phosphorylation. Retinal function after reattachment will be assessed by electroretinograms. Some of the drugs that will be tested (Ct-04 and fasudil) have already been approved for human use. We hope to establish the approximate dosage and mode of application to be tested in patients, if RhoA antagonists prove to be a useful adjunct to surgical reattachment.