脊髓背角 I-III 层中 GABA 能中间神经元的丧失导致脊髓损伤后 GABA 能紧张度降低和神经病理性疼痛。
Loss of GABAergic interneurons in laminae I-III of the spinal cord dorsal horn contributes to reduced GABAergic tone and neuropathic pain after spinal cord injury.
机构信息
Department of Anatomy and Neurobiology, Dalhousie University, Halifax, Nova Scotia, Canada.
出版信息
J Neurotrauma. 2010 Apr;27(4):729-37. doi: 10.1089/neu.2009.1166.
Abstract In this study we explore if loss of GABAergic inhibitory interneurons in the superficial dorsal horn of the spinal cord contributes to reduced GABAergic tone and neuropathic pain following spinal cord injury (SCI). A moderate contusion injury to T11 resulted in the development of mechanical hyperalgesia and thermal hyperalgesia below the level of the lesion in gad1:GFP mice that were alleviated by IP administration of the GABA transporter antagonist tiagabine. Six weeks following SCI a decreased number of GFP(+) neurons were observed in the dorsal horn of SCI animals relative to sham mice. Tissue from a mouse 2 weeks post-SCI was subsequently observed to express activated caspase-3, indicative of apoptosis, co-localized to some GFP(+) GABAergic neurons. Glutamate decarboxylase (GAD)65 and GAD67 immunohistochemical staining was reduced in the dorsal horn of SCI animals. This observation was confirmed in Western blots showing reduced immunoreactivity for GAD67, as well as GABA transporter (GAT)1. Reversal of post-SCI neuropathic pain by tiagabine suggests that reduced GABAergic tone may contribute to hyperalgesia symptoms. This is supported by the subsequent observation that SCI reduced the number of GFP(+) inhibitory neurons, and the finding that some GABAergic GFP(+) neurons undergo cell death at a time point consistent with the development of neuropathic pain following SCI. Concordantly, reductions in both GAD65 and GAD67 and GAT1 immunoreactivity also support the observation of a loss of GABAergic inhibition and the associated spinal interneurons.
摘要
在本研究中,我们探讨了脊髓背角浅层中 GABA 能抑制性中间神经元的缺失是否导致脊髓损伤(SCI)后 GABA 能张力降低和神经性疼痛。T11 中度挫伤导致 gad1:GFP 小鼠损伤以下部位出现机械性痛觉过敏和热痛觉过敏,而 IP 给予 GABA 转运体拮抗剂替加滨可缓解这些症状。SCI 后 6 周,与假手术小鼠相比,SCI 动物背角中 GFP(+)神经元数量减少。随后观察到 SCI 后 2 周的小鼠组织表达激活的 caspase-3,表明存在细胞凋亡,与一些 GFP(+)GABA 能神经元共定位。SCI 动物背角中谷氨酸脱羧酶(GAD)65 和 GAD67 的免疫组织化学染色减少。Western blot 进一步证实了这一观察结果,显示 GAD67 以及 GABA 转运体(GAT)1 的免疫反应性降低。替加滨逆转 SCI 后神经性疼痛表明,GABA 能张力降低可能导致痛觉过敏症状。这一观察结果得到了进一步的支持,即 SCI 减少了 GFP(+)抑制性神经元的数量,并且发现一些 GABA 能 GFP(+)神经元在与 SCI 后神经性疼痛发展一致的时间点发生细胞死亡。相应地,GAD65、GAD67 和 GAT1 免疫反应性的减少也支持 GABA 能抑制和相关脊髓中间神经元缺失的观察结果。