Dilley Andrew, Lynn Bruce, Pang See Jye
Department of Physiology, University College London, Gower Street, London WC1E 6BT, UK.
Pain. 2005 Oct;117(3):462-472. doi: 10.1016/j.pain.2005.08.018.
Patients with non-specific limb pain often show signs of nerve mechanosensitivity, i.e. local tenderness over nerve trunks and pain in response to limb movements that cause nerve stretch. In such patients a nerve lesion is not apparent, and it has been suggested that local neural inflammation may be a key factor. The present study examines the extent to which nerve fibres in regions of local inflammation respond to small stretches, and whether functional changes occur throughout the primary afferent neurone. A local neuritis was induced in adult rats by wrapping oxidised cellulose saturated in complete Freund's adjuvant (CFA) around the peroneal or sciatic nerves. A small cut was made in the perineurium of some of the peroneal lesioned animals. A- and C-fibre recordings were made 2-10 days post-surgery from filaments dissected proximal to the lesion. Local mechanosensitivity was assessed using a glass probe and by small stretches. Responses to stretch and local pressure were recorded in 7% of C- and 8% of A-fibres from the peroneal nerve following CFA treatment with the sheath opened. A smaller proportion of stretch sensitive fibres were seen in sciatic and peroneal nerves after CFA treatment alone (2% of C- and 3% of A-fibres), but such fibres were not seen in control preparations. The most responsive fibres fired to 3% stretch, which is within the range of nerve stretch seen during normal limb movements. Less than 1% of stretch sensitive fibres had peripheral fields, indicating that most had probably degenerated distally.
非特异性肢体疼痛患者常表现出神经机械敏感性迹象，即神经干局部压痛以及对引起神经拉伸的肢体运动产生疼痛反应。在这类患者中，神经损伤并不明显，有人提出局部神经炎症可能是一个关键因素。本研究考察局部炎症区域的神经纤维对小幅度拉伸的反应程度，以及初级传入神经元是否会发生功能变化。通过将浸泡在完全弗氏佐剂（CFA）中的氧化纤维素包裹在成年大鼠的腓神经或坐骨神经周围来诱发局部神经炎。对部分腓神经损伤动物的神经束膜做一个小切口。在手术后2 - 10天，从损伤近端分离出的细丝上记录A纤维和C纤维的活动。使用玻璃探针并通过小幅度拉伸来评估局部机械敏感性。在打开鞘膜的情况下，CFA处理后，腓神经中7%的C纤维和8%的A纤维对拉伸和局部压力有反应。单独使用CFA处理后，坐骨神经和腓神经中对拉伸敏感的纤维比例较小（C纤维的2%和A纤维的3%），但在对照制剂中未观察到此类纤维。反应最强烈的纤维在拉伸3%时放电，这在正常肢体运动时神经拉伸的范围内。不到1%的拉伸敏感纤维有外周野，这表明大多数纤维可能在远端已经退化。
