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，使人虚弱，由于对传统疗法反应不佳，这是一个重大的临床挑战。这些研究的基本假设和动机是，来自脊髓或周围神经损伤的严重慢性疼痛是由于脊髓抑制过程的丧失以及由此导致的背角疼痛传递神经元异常的过度兴奋，通过神经移植恢复脊髓抑制将缓解神经病理性疼痛。为了实现这一点，将对外周和中枢损伤诱导疼痛模型进行神经病理学和干细胞移植策略的评估。慢性缩窄性损伤模型(CCI)将用于周围神经病理性疼痛，奎宁酸模型(QUIS)将用于兴奋性脊髓损伤疼痛。目的1描述和比较CCI和QUIS后脊髓背角抑制性神经元的丢失和由此导致的夸大疼痛。目的2描述和比较CCI和QUIS后脊髓背角神经元的异常激活和过度兴奋性。这两个目标的研究将包括深入评估可能导致抑制性丧失和异常过度兴奋(GABA神经元丢失或功能障碍)的脊髓背角的形态和神经化学变化，感觉处理的变化(对伤害性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变化，以建立模型和治疗干预之间的比较基础。AIMS 3-5将探索使用神经前体移植来取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。AIM 3将通过外源性操作(营养因子休克)、遗传操作(阻断HLH转录因子Hes1以促进GABA能分化)和/或细胞选择(GAD启动子-GFP和FACS分选)为移植提供可靠且可重复的GABA能神经前体细胞来源。目的4将评估GABA能神经前体细胞移植策略在恢复脊髓抑制和减轻慢性神经病理性和中枢性疼痛方面的作用。目的5将评估嗜铬细胞和GABA能神经前体细胞共移植的策略，因为嗜铬细胞产生一种营养因子的混合物，可以改善神经干细胞的存活和分化，并可以减轻慢性神经病和脊髓损伤疼痛。这些研究的结果应该有助于改进治疗顽固性神经病理性疼痛的干预策略。

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.