单一腰6脊神经根结扎延长大鼠神经病理性疼痛发展期的研究

Study of single lumbar 6 spinal nerve root ligation extend the development period of neuropathic pain in rats

目的腰5和腰6脊神经根共同结扎是目前最常见的神经病理性疼痛鼠模型,但结扎后大鼠的机械触诱发痛会在24-72 h内迅速发展,时间窗过短,本课题组探索和研究了一种新型的神经病理性疼痛大鼠模型—单一腰6脊神经根结扎鼠模型。方法将36只大鼠随机分为空白对照组、腰5和腰6脊神经根结扎组、单一腰6脊神经根结扎组及假手术组,除单一腰6脊神经根结扎组18只外,其余3组每组6只大鼠;分别检测其50%机械缩爪阈值（50%PWT）。另取54只大鼠,随机分为空白对照组、腰5和腰6脊神经根结扎组、腰6脊神经根结扎组,各组大鼠只数分别为6只、24只、24只。采用蛋白免疫印迹法检测脊髓背角胶质纤丝酸性蛋白（GFAP）在结扎术后第1d、第7d、第14d和第28d的表达。结果单一腰6脊神经根结扎组产生了长期发展的机械触诱发痛（1-14d）;且大鼠同侧脊髓背角GFAP表达随之升高。结论单一腰6脊神经根结扎鼠模型可以作为研究神经病理性疼痛发展期具体机制的有效模型。

Objective The lumbar 5 and 6（L5/6） spinal nerve ligation（SNL） is one of the most widely used approaches rat models for neuropathic pain , results in the rapid development of mechanical allodynia within 24-72 h.However , the time of duration was too short , then our team explored and studied a new kind of neuropathy pain rat model of single lumbar 6 spinal nerve root ligation.Methods The first series of experiments were performed to examine the pain behavior of rats with different nerve ligations .36 rats were randomly divided into control group （n=6）,L5/6 nerve root ligation group（n=6）,single L6 nerve root ligation group （n=18）and sham operation group （n=6）. The mechanical allodynia of rats was assessed using a 50 %paw with drawal threshold （PWT）.The other 54 rats were randomly divided into control group （n=6）,L5/6 nerve ligation group（n=24）and L6 nerve root ligation group （ n=24 ） .The second series of experiments were performed using Western blots to evaluate dorsal horn glial fibrillary acidic protein （ GFAP） expression in different groups at different time points（1 d,7 d,14 d and 28 d）.For this series of experiments , Results In this study, a single L6 SNL induced prolonged development （1-14 days） of mechanical allodynia and gradually increased expression of GFAP in the ipsilateral dorsal horn .Conclusions Single L6 SNL might be used as an effective model for researching the development period of neuropathicpain and is thus worth further investigation .