Nociceptive responses and spinal plastic changes of afferent C-fibers in three neuropathic pain models induced by sciatic nerve injury in the rat
Nociceptive responses and spinal plastic changes of afferent C-fibers in three neuropathic pain models induced by sciatic nerve injury in the rat
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DOI：
10.1016/j.expneurol.2009.01.014
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发表时间：
2009-05-01
影响因子：
5.3
通讯作者：
Navarro, Xavier
中科院分区：
文献类型：
--
作者：
Casals-Diaz, Laura;Vivo, Meritxell;Navarro, Xavier
周围神经损伤引起初级传入纤维和脊髓回路的可塑性变化，这与神经病理性疼痛的出现有关。在这项研究中，我们比较了三种不同程度的损伤和对再生能力的影响的大鼠坐骨神经损伤模型：挤压神经损伤，慢性压迫性损伤（CCI）和备用神经损伤（SNI）。所有三种模型的特点是通过神经组织学，以描述损伤轴突的变性和再生过程。通过机械和热痛觉测试评价伤害性反应。在去神经支配期间，挤压动物在同侧爪上显示出比对侧更高的缩回阈值，而CCI和SNI动物显示出机械和热痛觉过敏。通过免疫组织化学标记L4-L 6脊髓切片上的非肽能（IB 4阳性）和肽能（P物质阳性）伤害性C纤维来评价中枢可塑性。挤压神经损伤和SNI后，我们观察到渐进性和持续减少IB 4和SP免疫标记在坐骨神经投射领域的浅层的背角，这只影响胫神经和腓神经投射区的SNI的情况下。CCI后SP免疫反应无明显变化，IB 4免疫反应面积最初减少，但在伤后第2周恢复至正常水平。因此，伤害性反应取决于损伤的类型，并且在部分坐骨神经损伤后脊髓的传入纤维的免疫反应性模式显示变化不太明显。虽然神经病理性疼痛的迹象出现在所有三个病变模型，伤害性反应和中央可塑性模式之间的差异。(C)2009 Elsevier Inc. All rights reserved.
Peripheral nerve injuries induce plastic changes on primary afferent fibers and on the spinal circuitry, which are related to the emergence of neuropathic pain. In this study we compared three models of sciatic nerve injury in the rat with different degrees of damage and impact on regeneration capability: crush nerve injury, chronic constriction injury (CCI) and spared nerve injury (SNI). All three models were characterized by means of nerve histology, in order to describe the degenerative and regenerative process of injured axons. Nociceptive responses were evaluated by mechanical and thermal algesimetry tests. Crush animals displayed higher withdrawal thresholds on the ipsilateral paw compared to the contralateral during the time of denervation, while CCI and SNI animals showed mechanical and thermal hyperalgesia. Central plasticity was evaluated by immunohistochemical labeling of non-peptidergic (IB4-positive) and peptidergic (substance P-positive) nociceptive C-fibers on L4-L6 spinal cord sections. After crush nerve injury and SNI, we observed progressive and sustained reduction of IB4 and SP immunolabeling at the sciatic projection territory in the superficial laminae of the dorsal horn, which affected only the tibial and peroneal nerves projection areas in the case of SNI. After CCI, changes on SP-immunoreactivity were not observed, and IB4-immunoreactive area decreased initially but recovered to normal levels on the second week post-injury. Thus, nociceptive responses depend on the type of injury, and the immunoreactivity pattern of afferent fibers at the spinal cord display changes less pronounced after partial than complete sciatic nerve injury. Although signs of neuropathic pain appear in all three lesion models, nociceptive responses and central plasticity patterns differ between them. (C) 2009 Elsevier Inc. All rights reserved.