Neural Transplants and Spinal Neuropathic Pain Processes

描述（由申请人提供）：外周或中枢神经系统损伤引起的疼痛通常是持续性的，使人衰弱，并且由于传统治疗方法效果不佳，因此提出了重大的临床挑战。本研究的基本假设和动机是脊髓或周围神经损伤引起的严重慢性疼痛是由于脊髓抑制过程的丧失和由此引起的背角疼痛传递神经元异常高兴奋性，通过神经移植恢复脊髓抑制将减轻神经性疼痛。为了实现这一目标，损伤性疼痛的外周和中枢模型将被评估为神经病理学和干细胞移植策略。慢性收缩损伤模型（CCI）用于周围神经性疼痛，准质酸模型（QUIS）用于兴奋性脊髓损伤疼痛。目的1将描述和比较CCI和QUIS后脊髓背角的抑制性神经元细胞损失和随之而来的夸大疼痛。目的2将描述和比较CCI和QUIS后脊髓背角神经元的异常激活和高兴奋性。这两个目标的研究将包括深入评估脊髓背角的形态学和神经化学变化，这些变化可能导致抑制性丧失和异常高兴奋性（GABA神经元丧失或功能障碍），感觉处理的改变（对有害和无害刺激的夸张行为反应和c-fos激活），并对背角神经元兴奋性的生理变化建立模型与治疗干预的比较基础。目的3-5将探讨使用神经祖细胞移植来替代周围神经或脊髓损伤后脊髓背角丢失或功能失调的抑制性神经回路。Aim 3将通过外部操作（营养因子休克）、遗传操作（阻断HLH转录因子Hes1以促进gabaergy分化）和/或细胞选择（GAD启动子- gfp和FACS分选）产生可靠且可重复的gabaergy神经祖细胞用于移植。目的4将评估gaba能神经祖细胞移植策略在恢复脊髓抑制和减轻慢性神经性和中枢性疼痛方面的作用。Aim 5将评估染色质细胞和gaba能神经祖细胞共移植策略，因为染色质细胞产生一系列营养因子，可改善神经干细胞的存活和分化，并可减轻慢性神经性和脊髓损伤疼痛。这些研究的发现将导致在难治性神经性疼痛的治疗中改进干预策略。

DESCRIPTION (provided by applicant): Pain from injury to the peripheral or central nervous system is often persistent and debilitating, and presents a significant clinical challenge as it does not respond well to traditional therapies. The underlying hypothesis and motivation for the proposed studies is that severe chronic pain from spinal cord or peripheral nerve injury results from loss of spinal inhibitory processes and consequent abnormal hyperexcitability in dorsal horn pain transmission neurons, and that restoration of spinal inhibition by neural transplantation will alleviate neuropathic pain. In order to accomplish this, peripheral and central models of injury-induced pain will be evaluated for neuropathology and stem cell transplantation strategies. The chronic constriction injury model (CCI) will be used for peripheral neuropathic pain and the quisqualic acid model (QUIS) for excitotoxic spinal cord injury pain. Aim 1 will characterize and compare the inhibitory neuronal cell loss in the spinal dorsal horn and consequent exaggerated pain following CCI and QUIS. Aim 2 will characterize and compare the abnormal activation and hyperexcitability of spinal dorsal horn neurons following CCI and QUIS. Studies in these 2 aims will include in depth evaluation of morphological and neurochemical changes in the spinal dorsal horn that likely contribute to inhibitory loss and abnormal hyperexcitability (GABA neuronal loss or dysfunction), alterations in sensory processing (exaggerated behavioral responses and c-fos activation in response to noxious and innocuous stimuli), and physiological alterations in dorsal horn neuronal excitability to establish a comparative basis between the models and treatment interventions. Aims 3-5 will explore the use of neural progenitor transplants to replace lost or dysfunctional inhibitory neurocircuitry in the spinal dorsal horn following peripheral nerve or spinal cord injury. Aim 3 will generate a reliable and reproducible source of GABAergic neural progenitor cells for transplantation using extrinsic manipulation (trophic factor shock), genetic manipulation (blocking HLH transcription factor Hes1 to promote GABAergic differentiation) and/or cell selection (GAD promoter-GFP and FACS sorting). Aim 4 will evaluate GABAergic neural progenitor transplantation strategies in restoring spinal inhibition and alleviating chronic neuropathic and central pain. Aim 5 will evaluate chromaffin cell and GABAergic neural progenitor co-grafting strategies, as chromaffin cells produce a cocktail of trophic factors which improve neural stem cell survival and differentiation, and can reduce chronic neuropathic and SCI pain. Findings from these studies should lead to improved interventive strategies in the management of intractable neuropathic pain.