Neural Stability after Retinal Detachment

描述（由申请人提供）：视网膜脱离修复后的视力恢复通常令人失望，超过一半的治疗患者报告视力低于正常。视网膜神经元在脱离后经历了戏剧性的结构可塑性，包括杆轴突的回缩，锥终末的变圆，以及双极和水平细胞的发芽。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。有人认为，这种突触重塑有助于视力恢复不良。在视网膜细胞培养物中，RhoA-Rho激酶（ROCK）信号级联的激活主要负责视杆轴突回缩。因此，本申请测试了RhoA拮抗剂和视网膜手术的组合疗法可以通过防止或降低突触可塑性来显著改善修复脱离的视网膜后的视觉结果的假设。将在眼睛与人眼相似的成年猪上测试这一假设，重点是以下具体目的：1）测试抑制RhoA、ROCK或其底物活性的RhoA拮抗剂是否会阻止由脱离引起的结构性突触变化，包括杆轴突回缩、杆-双极突触溶解、锥体末端形态学变化和双极细胞发芽。还将检查对神经胶质细胞反应性的影响; 2）确定RhoA相关药物是否可以在脱离后应用，这是一种更具治疗相关性的情况，如果可以，在损伤后多久;以及3）确定用RhoA相关药物治疗的脱离视网膜是否确实有助于再附着手术后的视觉结构和功能恢复。将通过免疫组织化学、图像分析和共聚焦激光扫描和电子显微镜评估形态学。Rho信号传导的活性水平和时程将通过多种组分的生化测定来确定，包括RhoA活化和肌球蛋白轻链磷酸化。复位后的视网膜功能将通过视网膜电图进行评估。一些将要测试的药物（Ct-04和法舒地尔）已经被批准用于人类。如果RhoA拮抗剂被证明是一种有用的辅助手术复位，我们希望建立一个近似的剂量和模式的应用程序进行测试的患者。 公共卫生相关性：视网膜脱离修复后的视力结果仍然令人失望，即使在成功复位手术后数年。基于在体外预防有害的感光细胞突触变化的有效性，提出了一种新的治疗视网膜脱离的方法。该治疗包括眼内应用RhoA拮抗剂结合相对快速的视网膜复位。

DESCRIPTION (provided by applicant): 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. PUBLIC HEALTH RELEVANCE: Visual outcomes after repair of retinal detachment remain disappointing even years after successful reattachment surgery. Based on the effectiveness of preventing deleterious photoreceptor synaptic change, in vitro, a new therapy is proposed for retinal detachment. The therapy consists of intraocular application of RhoA antagonists combined with relatively rapid retinal reattachment.