Optogenetics to improve hand function after spinal cord injury.

项目总结/摘要 恢复手和手臂功能是颈脊髓损伤患者的最高治疗优先事项 损伤本研究的目的是开发和测试一种新的方法来提高手和手臂的恢复 脊髓损伤后的功能我们建议使用颈脊髓的光遗传学刺激， 改善功能并揭示脊髓刺激导致恢复的机制。 我们的初步数据表明，当 动物在临床上真实的颈脊髓挫伤后接受光遗传学脊髓刺激 损伤光遗传学光刺激可以通过直接激活神经回路以及还通过激活神经回路来提供益处。 增加受伤脊髓的血流量在这里，我们建议比较功能恢复结果 从光遗传学和电脊髓刺激，以及电和光的组合， 刺激递送至不表达光遗传学蛋白的幼稚动物。 我们的实验是由一种新型的多功能电极，允许光学和电学 刺激传递到啮齿动物的脊髓表面。这些柔性聚合物电极将被 在目的1中改进了将慢性光遗传学和硬膜外电刺激递送到大鼠颈脊髓。 因此，所有动物将在随机分配至治疗组之前植入相同的硬件， 允许直接比较Aim 2中的光遗传学和电刺激。 我们将使用我们建立的脊髓挫伤大鼠模型，动物在那里接受训练， 精确的前肢到达，以准确量化受伤后的功能恢复。我们的合作团队拥有 开发了一种可靠的病毒转导光遗传蛋白的方法， 在非转基因大鼠颈脊髓的神经元中表达。治疗6周后， 光遗传学和硬膜外电刺激，我们将探讨每种治疗导致的机制， 目标3中前肢功能的延长恢复。我们将进行终末电生理学检查并记录 在相同的动物中由光和电刺激引起的反应。 我们的初步数据表明，上调轴突生长后光遗传刺激。我们将 使用逆行跨突触追踪和组织学来量化绕过损伤的新回路形成。 标记的神经元将与通过光遗传学刺激与硬膜外刺激激活的神经元共定位， 结合原位杂交和免疫组织化学来阐明恢复的机制。 总之，我们建议揭示光遗传学脊髓刺激导致 脊髓损伤后前肢功能几乎完全恢复。一旦理解，我们期望这些 该机制直接激发了对大脑和脊髓的一系列神经创伤的治疗。

Project Summary/Abstract Restoration of hand and arm function is the highest treatment priority for people with cervical spinal cord injury. The goal of this research is to develop and test a novel method to improve recovery of hand and arm function after spinal cord injury. We propose to use optogenetic stimulation of the cervical spinal cord to both improve function and to uncover the mechanisms by which spinal cord stimulation leads to recovery. Our preliminary data demonstrate both a rapid and near complete recovery of forelimb function when animals receive optogenetic spinal cord stimulation following a clinically-realistic cervical spinal cord contusion injury. Optogenetic light stimulation may provide benefits by both directly activating neural circuits and also by increase blood flow to the injured spinal cord. Here we propose to compare the functional recovery resulting from optogenetic and electrical spinal cord stimulation, as well as the combination of electrical and light stimulation delivered to naïve animals that do not express optogenetic proteins. Our experiments are enabled by a novel multifunctional electrode that permits both optical and electrical stimulation to be delivered to the surface of the spinal cord in rodents. These flexible polymer electrodes will be refined in Aim 1 to deliver chronic optogenetic and epidural electrical stimulation to the rat cervical spinal cord. Thus all animals will be implanted with identical hardware prior to being randomized into treatment groups to permit a direct comparison between optogenetic and electrical stimulation in Aim 2. We will use our established rat model of spinal contusion injury where animals are trained to perform precision forelimb reaching to accurately quantify recovery of function after injury. Our collaborative team has developed a reliable method of viral transduction of optogenetic proteins such that light-sensitive ion channels are expressed in neurons of the non-transgenic rat cervical spinal cord. Following 6-weeks of treatment with optogenetic and epidural electrical stimulation, we will explore the mechanisms by which each treatment leads to prolonged recovery of forelimb function in Aim 3. We will perform terminal electrophysiology and record the responses evoked by both optical and electrical stimulation in the same animals. Our preliminary data demonstrate an upregulation of axon growth following optogenetic stimulation. We will use retrograde trans-synaptic tracing and histology to quantify new circuit formation bypassing the injury. Labelled neurons will be co-localized with the neurons activated by optogenetic vs. epidural stimulation using combined in-situ hybridization and immunohistochemistry to illuminate mechanisms of recovery. In summary, we propose to uncover the mechanisms by which optogenetic spinal cord stimulation leads to nearly complete recovery of forelimb function following spinal cord injury. Once understood, we expect these mechanism to directly inspire treatments for a range of neurological traumas to the brain and spinal cord.