Therapeutic potential and the critical site of action of non-addicting glibenclamide in neuropathic pain

背景：几乎一半的退伍军人经历慢性疼痛，这是不成比例地大于 2500万美国平民患有严重的慢性疼痛。慢性疼痛是常见的 与军事和恐怖活动有关的创伤后遗症。大多数战场创伤都是暴露在 四肢，导致周围神经损伤引起的神经性疼痛发生率很高。阿片类药物使用障碍 和正在进行的“阿片类药物流行病”部分是由合法使用阿片类药物处方神经病 痛苦部署后，15%的退伍军人使用阿片类药物，而普通人群的这一比例为4%， 退伍军人，阿片类药物的使用和自杀之间有直接的相关性。靶向替代非阿片类 使用非成瘾药物控制疼痛的途径是神经性疼痛研究的主要目标。外围设备后 神经损伤（PNI），细胞因子和趋化因子在中枢上调，包括在背角星形胶质细胞中， 其中它们在机制上有助于神经性疼痛的发病机制。背部反应性星形胶质细胞 角表现出慢性激活的促炎分泌（CAPS）表型，其特征在于 许多因子的分泌，包括白细胞介素-6（IL-6）、趋化因子C-C基序配体2（CCL 2）和 趋化因子C-X-C基序配体1（CXCL 1），其中每一个单独地已被证明有助于神经病理性 疼痛行为PNI后星形胶质细胞CAPS表型有助于炎症和神经元凋亡。 通过神经元趋化因子受体过度活化，导致神经性疼痛。我们的试验数据表明， 在神经病理性疼痛的小鼠坐骨神经袖套模型中， （SUR 1）与低剂量格列本脲每日给药，持续数周，治疗开始于 PNI后第21天的慢性期导致以下方面的显著减少：（i）机械性异常性疼痛、热痛觉过敏 和位置逃避/回避;（ii）背角星形胶质细胞表达IL-6、CCL 2和CXCL 1。 描述：该项目具有临床相关目的，旨在确定治疗潜力、耐久性， 和格列本脲治疗PNI诱导的神经病理性疼痛行为的关键作用部位。四个单独 使用鼠坐骨神经袖套模型在雄性和雌性中计划实验， 仅在慢性期，即PNI后3周。在这些实验中，我们将检查：（a）各种能力 有效逆转神经病理性疼痛行为的全身和鞘内剂量的格列本脲（机械性疼痛） 异常性疼痛、热痛觉过敏、位置逃避/回避、焦虑和抑郁样行为），以及相关的 运动功能障碍;（B）全身性格列本脲逐渐消除 DRG/背角，与观察到的异常性疼痛的逐渐消退相关;（c） 治疗停止后的格列本脲治疗;和（d）的解剖学和细胞作用部位 格列本脲将研究小鼠长达11周的神经性疼痛行为和运动功能; DRG和 将研究背角组织的神经炎症，包括星形胶质细胞和小胶质细胞活化， SUR 1-TRPM 4、IL-6、CCL 2和CXCL 1的表达。该项目是第一个研究神经病理学的影响， 格列本脲抑制SUR 1的疼痛，安全，非成瘾性，可重新用于治疗 神经性疼痛，从而大大改善受影响的退伍军人的功能。

BACKGROUND: Almost half of Veterans experience chronic pain, which is disproportionately greater than the 25 million Americans in the civilian population who suffer from significant chronic pain. Chronic pain is a common sequela of military- and terror-related injuries. The majority of battlefield wounds involve injuries to exposed limbs, resulting in high rates of neuropathic pain caused by damage to a peripheral nerve. Opioid use disorder and the ongoing “opioid epidemic” are driven in part by the legitimate use of opioids prescribed for neuropathic pain. Post-deployment, 15% of military Veterans use opioids, compared to 4% of the general population, and in Veterans, there is a direct correlation between the use of opioids and suicide. Targeting alternative non-opioid pathways for pain control using non-addicting drugs is a major goal of neuropathic pain research. After peripheral nerve injury (PNI), cytokines and chemokines are upregulated centrally, including in dorsal horn astrocytes, where they contribute mechanistically to the pathogenesis of neuropathic pain. Reactive astrocytes in the dorsal horn exhibit a chronically activated, pro-inflammatory secretory (CAPS) phenotype characterized by the secretion of numerous factors, including interleukin-6 (IL-6), chemokine C-C motif ligand 2 (CCL2) and chemokine C-X-C motif ligand 1 (CXCL1), each of which individually has been shown to contribute to neuropathic pain behaviors. The post-PNI astrocytic CAPS phenotype contributes to both inflammation and neuronal hyperactivation via neuronal chemokine receptors, leading to neuropathic pain. Our pilot data demonstrate the novel findings that, in the murine sciatic nerve cuff model of neuropathic pain, inhibiting sulfonylurea receptor 1 (SUR1) with low-dose glibenclamide administered daily over several weeks, with treatment beginning during the chronic phase at day21 after PNI, causes marked reductions in: (i) mechanical allodynia, thermal hyperalgesia and place escape/avoidance; (ii) dorsal horn astrocyte expression of IL-6, CCL2 and CXCL1. DESCRIPTION: This project has the clinically relevant aim of establishing the therapeutic potential, durability, and critical site of action of glibenclamide treatment in neuropathic pain behaviors induced by PNI. Four separate experiments are planned in males and females using the murine sciatic nerve cuff model, with treatments applied only during the chronic phase, 3 weeks after PNI. In these experiments, we will examine: (a) the ability of various doses of systemic and intrathecal glibenclamide to effectively reverse neuropathic pain behaviors (mechanical allodynia, thermal hyperalgesia, place escape/avoidance, anxiety and depression-like behaviors), and related motor dysfunction; (b) the ability of systemic glibenclamide to gradually extinguish neuroinflammation in the DRG/dorsal horn, for correlation with the observed gradual extinction of allodynia; (c) the durability of glibenclamide treatment after treatment cessation; and (d) the anatomical and cellular site of action of glibenclamide. Mice will be studied up to 11 weeks for neuropathic pain behaviors and motor function; DRG and dorsal horn tissues will be studied for neuroinflammation, including astrocyte and microglial activation, and expression of SUR1-TRPM4, IL-6, CCL2 and CXCL1. This project is the first to study the effects in neuropathic pain of SUR1 inhibition by glibenclamide, which is safe, non-addicting and could be repurposed for the treatment of neuropathic pain, thereby greatly improving the function of affected Veterans.