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发生剧烈的结构可塑性，包括杆状轴突缩回，锥体末端变圆，双极细胞和水平细胞发芽。在动物模型中，一些变化发生在视网膜损伤后数小时内。有研究表明，这种突触重构导致视力恢复不良。在视网膜细胞培养中，RhoA-Rho激酶（ROCK）信号级联的激活是杆状轴突收缩的主要原因。因此，该应用验证了rhoa拮抗剂和视网膜手术联合治疗可能通过防止或减少突触可塑性显著改善分离视网膜修复后的视力结果的假设。这一假设将在眼睛与人眼相似的成年猪身上进行测试，重点关注以下具体目标：1)测试抑制RhoA、ROCK或其底物活性的RhoA拮抗剂是否会阻止脱离引起的突触结构变化，包括杆轴突收缩、杆-双极突触溶解、锥体末端形态改变和双极细胞发芽。对神经胶质细胞反应性的影响也将被检查；2)确定是否可以在脱离后使用rhoa相关药物，这是一种更具有治疗意义的情况，如果可以，则在损伤后多长时间；3)确定使用rhoa相关药物治疗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。形态学将通过免疫组织化学、图像分析、共聚焦激光扫描和电子显微镜进行评估。Rho信号的活性水平和时间过程将通过多种成分的生化分析来确定，包括RhoA激活和肌球蛋白轻链磷酸化。再附着后的视网膜功能将通过视网膜电图评估。一些将被测试的药物（Ct-04和法舒地尔）已经被批准用于人类使用。如果RhoA拮抗剂被证明是手术再附着的有效辅助手段，我们希望建立用于患者试验的近似剂量和应用模式。

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.