兔坐骨神经急性牵拉伤模型的制作:MRI与病理对照

Acute sciatic nerve traction injury in rabbits:MRI and pathology comparative study

目的模拟人类周围神经牵拉伤机制,通过MRI与病理对照,探讨兔坐骨神经牵拉伤模型的制作。方法20只新西兰大白兔,随机选取一侧坐骨神经,使用无齿钳牵拉神经制作牵拉伤。每只兔在术前及牵拉伤后第3天均行双侧坐骨神经MRI,检查序列包括3DT2WI、T1WI、3DT2WI/SPIR、Mixed多回波序列(测量T1值)及SE多回波序列(测量T2值),并进行病理检查及后肢功能的评价。结果兔坐骨神经牵拉伤后,牵拉侧后肢运动功能及神经反射功能出现障碍,T2WI及T2WI/SPIR序列坐骨神经增粗,信号增高。损伤后与损伤前相比,牵拉近段、牵拉段、牵拉远段神经的T1值及T2值均升高,差异有统计学意义(P<0.05)。牵拉伤神经病理表现为髓鞘崩解、轴突丧失。结论兔坐骨神经牵拉伤后MRI表现为神经增粗,T1、T2时间延长,通过病理对照,模型制作成功。

Objective To approach the model of acute sciatic nerve traction injury in rabbits simulating injury mechanisms in human peripheral nerve by comparison MRI with pathology.Methods One side of sciatic nerve of all 20 New Zealand rabbits were randomly selected to be tracted by smooth forceps to produce the traction injury.The sciatic nerve of the other side of each rabbit was exposed surgically,but not tracted,and defined as the sham-operated group.MRI examination of bilateral sciatic nerves was performed before surgery and at 3 days after traction injury.The MRI examinations consisted of 3D T2-weighted imaging,T1-weighted imaging,3D T2-weighted imaging with SPIR,mixed multiple echo(T1 calculation)and SE multiple echo(T2 calculation)sequences.After MRI examination the nerves were sampled for pathological examination.And the function of hind limbs of each rabbit was record.Results After sciatic nerve traction injury,the motor and reflex function of injured hind limb were abnormal.On MR imaging,the injured sciatic nerve showing high signal intensity on 3D T2WI and T2WI/SPIR,and myelin disaggregation and axon loss histologically.The T1 and T2 relaxation time of proximal segment,tracted segment and distal segment of sciatic nerve after injury were higher than that before injury.Conclusion The injured nerve is characterized as thickened in size and increased T1 and T2 relaxation time.By correlation of MR imaging with pathology,the acute sciatic nerve traction injury animal mode is successfully produced in rabbits.