兔坐骨神经牵拉伤的磁化传递成像与病理对比

Sciatic nerve traction injury in rabbits: Comparative study on magnetization transfer imaging and pathology

目的探讨坐骨神经牵拉伤后磁化传递率(MTR)改变的病理基础。方法对20只新西兰大白兔牵拉坐骨神经主干,建立坐骨神经牵拉伤模型,分别于术前、术后第1、3天、1、2、3、4、6、8、10周进行双侧坐骨神经MR检查和病理组织学检查。结果坐骨神经牵拉伤后MTR下降,早期下降明显,后期逐渐回升;神经损伤早期主要表现为炎症反应、神经变性,后期主要为施万细胞增生与神经纤维再生。牵拉伤后各段坐骨神经的MTR下降程度不同,牵拉段MTR下降最为明显。结论 MTR的动态变化能反映兔坐骨神经牵拉伤后的病理变化过程和神经损伤程度,可作为评价预后及疗效的补充手段。

Objective To investigate the pathological basis of the magnetization transfer ratio（MTR） changes of rabbit＇s sciatic nerve after traction injury.Methods MR examination was performed before and 1 day,3 days,1,2,3,4,6,8 and 10 weeks after traction injury of sciatic nerve in 20 rabbits.The injured segment,the proximal and distal segments of the sciatic nerves were obtained for light microscopic and electric microscopic examination.Results After injury,the MTR values of sciatic nerve descended obviously in earlier stage,and then gradually rose later.After injury,the sciatic nerve mainly manifested inflammation reaction and degeneration,including myelin disaggregation and axon lost in the early stage,exhibited Schwann cell proliferation and nerve fiber regeneration in the later stage.Differences of MTR values were dependent on the site along the same injured nerve,with the most pronounced of MTR values descended observed in the most severely damaged portion of the injured nerve.Conclusion After traction injury of rabbit＇s sciatic nerve,the change of MTR can reflect the pathological change and the severity of injury,therefore can be regarded as assistant index for prognostic and therapeutic evaluation.