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和使人衰弱的，并提出了重大的临床挑战，因为它对传统疗法的反应不佳。提出的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随后的背角疼痛传递神经元的异常过度兴奋，并且通过神经移植恢复脊髓抑制将减轻神经性疼痛。为了实现这一点，外周和中枢模型的损伤引起的疼痛将评估神经病理学和干细胞移植策略。慢性压迫性损伤模型（CCI）将用于外周神经性疼痛，使君子酸模型（QUIS）将用于兴奋性毒性脊髓损伤疼痛。目的1将描述和比较CCI和QUIS后脊髓背角抑制性神经元细胞丢失和随后的过度疼痛。目的2比较CCI和QUIS后脊髓背角神经元的异常激活和过度兴奋。这两个目标的研究将包括深入评价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过度兴奋（GABA神经元损失或功能障碍），感觉处理的改变（对有害和无害刺激的夸大行为反应和c-fos激活），以及背角神经元兴奋性的生理改变，以建立模型和治疗干预之间的比较基础。目的3-5将探索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中丢失或功能障碍的抑制性神经回路。目的3将使用外源性操作（营养因子休克）、遗传操作（阻断HLH转录因子Hes 1以促进GABA能分化）和/或细胞选择（GAD启动子-GFP和FACS分选）产生用于移植的GABA能神经祖细胞的可靠且可重复的来源。目的4探讨γ-氨基丁酸能神经前体细胞移植治疗脊髓抑制和慢性神经源性及中枢性疼痛的疗效。目的5将评估嗜铬细胞和GABA能神经祖细胞共移植策略，因为嗜铬细胞产生营养因子的鸡尾酒，其改善神经干细胞存活和分化，并且可以减轻慢性神经性疼痛和SCI疼痛。这些研究的结果应该会导致在顽固性神经病理性疼痛的管理改善干预策略。

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.