Transient cervical nerve root compression in the rat induces bilateral forepaw allodynia and spinal glial activation: Mechanical factors in painful neck injuries
Transient cervical nerve root compression in the rat induces bilateral forepaw allodynia and spinal glial activation: Mechanical factors in painful neck injuries
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DOI：
10.1097/01.brs.0000176239.72928.00
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发表时间：
2005-09-01
期刊：
影响因子：
3
通讯作者：
Winkelstein, BA
中科院分区：
文献类型：
--
作者：
Hubbard, RD;Winkelstein, BA
研究设计。目的建立一种短暂性颈神经根压迫大鼠体内模型。目的探讨压迫颈神经根产生行为超敏反应的可能性及其对压迫的依赖性。背景资料摘要。在临床上，神经根损伤被假设为颈部疼痛的潜在来源，特别是因为颈神经根在颈部负荷过程中存在损伤的机械风险。神经根结扎腰椎神经根病模型显示，机械性异常痛和脊髓胶质细胞改变依赖于神经根变形程度。然而，尚无研究证实颈神经根受压是引起疼痛的原因。用微血管夹在C7神经根上单侧瞬时施加10和60 g的压力[gf]，每组12个。在另一组大鼠（n = 12）中也进行假手术。术后监测双侧前爪机械性异常痛7天。第7天，在行为超敏的情况下，用免疫组织化学方法评估脊髓胶质细胞的激活，以研究其对神经根压缩力的依赖。损伤后观察到双侧异常性疼痛，与假手术和基线反应相比显著（P < 0.042）增加。在10和60 gf损伤之间没有发现异常性疼痛的差异。在同侧背角受压后观察到星形细胞和小胶质细胞的激活，只有星形细胞的激活与异常性疼痛模式平行。结果表明，短暂性颈神经根受压后持续疼痛症状的力阈值小于10gf。研究结果还表明，脊髓胶质细胞的激活可能与行为敏感性有关，并可能调节颈神经根介导的疼痛。
Study Design. An in vivo rat model of transient cervical nerve root compression.Objectives. To investigate the potential for cervical nerve root compression to produce behavioral hypersensitivity and examine its dependence on compression.Summary of Background Data. Clinically, nerve root injury has been hypothesized as a potential source of neck pain, particularly because cervical nerve roots are at mechanical risk for injury during neck loading. Lumbar radiculopathy models of nerve root ligation show that mechanical allodynia and spinal glial changes depend on nerve root deformation magnitude. However, no investigation has been performed to examine cervical nerve root compression as a cause of pain.Methods. Two compressive forces ( 10 and 60 grams force [gf]) were transiently applied to the C7 nerve roots unilaterally using microvascular clips in separate groups ( n = 12 each). Sham procedures were also performed in a separate group of rats ( n = 12). Bilateral forepaw mechanical allodynia was monitored after surgery for 7 days. On day 7, spinal glial activation was assessed using immunohistochemistry to investigate its dependence on nerve root compressive force, in the context of behavioral hypersensitivity.Results. Bilateral allodynia was observed following injury, which was significantly ( P < 0.042) increased over sham and baseline responses. No difference in allodynia was found between the 10 and 60 gf injuries. Astrocytic and microglial activation were observed in the ipsilateral dorsal horn following compression, with only astrocytic activation paralleling allodynia patterns.Conclusions. Results imply a force threshold exists less than 10 gf for persistent pain symptoms following transient cervical nerve root compression. Findings also suggest that spinal glial activation may be related to behavioral sensitivity and may modulate cervical nerve root mediated pain.