可量化型小鼠坐骨神经缩窄性神经病理痛模型建立及评估

Establishment and Evaluation of Quantifiable Neuropathic Pain Model of Sciatic Nerve Constriction in Mice

目的:建立并评估可量化型小鼠坐骨神经缩窄性神经病理痛模型。方法:用分级坐骨神经结扎的方法建立动物模型,即将小鼠随机分为N0、N1、N2、N4组,暴露坐骨神经主干部位,N1、N2、N4组小鼠分别结扎坐骨神经1、2、4道,每个结之间间隔1 mm;N0组只游离神经,不作任何结扎。通过测定小鼠右后爪热痛阈值,电镜观察坐骨神经超微结构,免疫组化检测小胶质细胞OX-42的荧光积分光密度值(IOD),酶联免疫吸附(ELISA)法测定脊髓白介素(IL-1β、IL-6)和肿瘤坏死因子(TNF-α)的浓度对模型进行评估。结果:与N0组相比,N1、N2和N4组术后热痛阈值较术前明显下降,坐骨神经纤维广泛洋葱化改变,轴索溶解或消失,雪旺氏细胞水肿、坏死,异常髓鞘所占比例增加,脊髓IL-1β、IL-6和TNF-α表达不同程度上升;N2、N4组脊髓小胶质细胞OX-42的IOD显著增加。结论:小鼠可量化型坐骨神经缩窄模型呈现不同程度的神经病理性疼痛、坐骨神经不同程度的髓鞘病变、脊髓小胶质细胞活化及脊髓IL-1β、IL-6和TNF-α表达增加;这一模型的建立可为神经病理性疼痛等的研究提供更利于准确评估的病理模型。

Objective： To establish and assess a quantifiable neuropathic pain model of sciatic nerve constriction in mice.Methods： Animal model was established by graded sciatic ligation. The mice were randomly divided into groups marked as N0,N1,N2 and N4. The sciatic nerve trunk was exposed,and then the mice in the N1,N2 and N4 group were ligated at sciatic nerve 1,2 and 4 respectively,with 1 mm interval between each knot. The mice in the N0 group was treated without any ligation but separated nerve from the surrounding connective tissue. The model was evaluated by the determination of pain threshold for heat in the right hind paw of mice,observation of sciatic nerve ultrastructure with electron microscope,quantification of the integral optical density（ IOD） of OX-42 in spinal microglia by immunohistochemistry,detection of the concentration of interleukin（ IL-1β and IL-6） and tumor necrosis factor（ TNF-α） in spinal by enzyme linked immunosorbent assay（ ELISA）.Results： Compared with N0 group,the postoperative pain threshold of the N1,N2 and N4 group was significantly decreased.The sciatic nerve fiber showed the extensive onion-like change,the axon dissolved or disappeared,Schwann cells emerged edema and necrosis,and the proportion of abnormal myelin sheath was increased. The expression of IL-1 β,IL-6 and TNF-α in spinal were up-regulated with varying degrees. The IOD of OX-42 in spinal microglia of the N2 and N4 group were significantly increased. Conclusion： The quantifiable mice model of sciatic nerve constriction can show the neuropathic pain and sciatic nerve myelin sheath lesion with varying degrees,as well as the activation of spinal microglia and up-regulated expression of IL-1β,IL-6 and TNF-α in spinal,which provides the pathological model with more accurate assessment for the research of neuropathic pain.