Inhibition of P2X7R in the amygdala ameliorates symptoms of neuropathic pain after spared nerve injury in rats
Inhibition of P2X7R in the amygdala ameliorates symptoms of neuropathic pain after spared nerve injury in rats
复制标题
抑制杏仁核中的 P2X7R 可改善大鼠神经损伤后的神经性疼痛症状
DOI：
10.1016/j.bbi.2020.04.030
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发表时间：
2020-08-01
影响因子：
15.1
通讯作者：
Yang, Fengrui
中科院分区：
文献类型：
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作者：
Hu, Xiaoling;Liu, Yiming;Yang, Fengrui
杏仁核回路和P2 X7受体（P2 X7 R）在神经病理性疼痛（NP）的调节中起重要作用。然而，很少有人知道杏仁核中的P2 X7 R的调节NP的功能作用。本研究旨在评价杏仁核内微量注射P2 X7 R拮抗剂A-438079对NP的抑制作用，并探讨其可能的作用机制。选用雄性SD大鼠，通过保留神经损伤（SNI）建立NP动物模型。SNI大鼠随机接受慢性双侧微量注射A-438079（100 pmol/侧）或生理盐水通过套管进入杏仁核。用von Frey单丝测量机械缩爪阈值（MWT）和热缩爪持续时间（TWD）。此外，采用悬尾试验（TST）、强迫游泳试验（FST）、旷场试验（OFT）和蔗糖偏好试验（SPT）评估抑郁和焦虑样行为。免疫荧光法检测脊髓胶质细胞酸性蛋白（GFAP）、钙离子结合接头分子1（IBA-1）和连接蛋白43（Cx43）的表达。此外，通过蛋白质印迹法评估脊髓中生长相关蛋白43（GAP 43）水平的变化。我们的数据显示，A-438079长期治疗增加了SNI后第11-21天的MWT并减少了TWD，同时减少了抑郁样和焦虑样行为。A-438079给药显著减弱了SNI后小胶质细胞和星形胶质细胞中IBA-1和GFAP的免疫反应性升高。此外，由于SNI导致的脊髓中GAP-43表达的降低被A-438079显著减弱。然而，当同时给予A-438079和P2 X7 R的药理学激动剂（BzATP）时，A-438079单独引起的所有效应均被逆转。简而言之，我们的研究揭示了抑制杏仁核中P2 X7 R对NP相关症状的保护作用，可能归因于其对脊髓小胶质细胞和星形胶质细胞的抑制作用。
The amygdala circuitry and P2X7 receptor (P2X7R) have both been shown to play important roles in the modulation of neuropathic pain (NP). However, little is known about the functional role of P2X7R in the amygdala for the regulation of NP. This study aims to evaluate the alleviative effect of intra-amygdala micro-infusion of a pharmacological antagonist of P2X7R (A-438079) on NP and explore its possible mechanism of action. Male Sprague-Dawley rats were used to construct the animal model of NP through spared nerve injury (SNI). The SNI rats randomly received chronic bilateral microinjection of A-438079 (100 pmol/side) or saline into the amygdalae via cannulas. Mechanical paw withdrawal threshold (MWT) and thermal withdrawal duration (TWD) were measured by von Frey monofilaments. Besides, tail suspension test (TST), forced swimming test (FST), open field test (OFT) and sucrose preference test (SPT) were performed to assess depression- and anxiety-like behaviors. Immunofluorescence assay was employed to determine the levels of glial fibrillary acidic protein (GFAP), ionized calcium binding adaptor molecule 1 (IBA-1) and connexin 43 (Cx43) in the spinal cord. In addition, the change of growth associated protein 43 (GAP43) level in the spinal cord was assessed by Western blot. Our data showed that chronic treatment with A-438079 increased MWT and decreased TWD on days 11-21 post-SNI while decreased depression-like and anxiety-like behaviors. A-438079 administration significantly attenuated the elevated immunoreactivities of IBA-1 and GFAP in microglia and astrocytes after SNI. Furthermore, the decreased expression of GAP-43 in the spinal cord due to SNI was significantly attenuated by A-438079. However, when A-438079 and a pharmacological agonist (BzATP) of P2X7R were given simultaneously, all the effects caused by A-438079 alone were reversed. In brief, our study revealed the protective role of inhibiting P2X7R in the amygdala against symptoms associated with NP, possibly attributing to its inhibitory effects on spinal microglia and astrocytes.