Objective:To study the relationship between magnetization transfer imaging (MTR)value and limb func-tion in stretched injury of sciatic nerve with various time points in rabbits.Methods:Twenty New Zealand rabbits were se-lected,their right hind limbs were operated to create model with reversible stretched injury of sciatic nerve,while sham operation was performed in the left hind limbs.They were randomly divided into two groups.MTR was carried out on bila-teral hind limbs of group A (n=12)at different time points including 1d before the operation and day 1,day 3 as well as 1w,2w,4w,6w and 8w after operation consecutively.The MTR values of the distal portion of injured sciatic nerve and the sham operated sciatic nerve were measured.The function scores including toe reflection,Tarlov score were evaluated.The correlation between MTR values and limb function scores were analyzed.Histology examination was performed at the same time points in group B (n=8).Results:The MTR value of the distal portion of stretched sciatic nerve obviously decreased 1d after the operation and reached to the lowest in the second week,then gradually increased and returned to normal level from the 4~8w.The statistical differences of MTR value at each time points between the distal portion of the injured nerve and the contra-lateral were existed (P <0.05 ).The toe reflection and Tarlov score decreased to the lowest 1d after the injury,kept in low level 1d to 1w after injury,the function scores gradually recovered 2~8w afterwards.The MTR values of the distal segment of stretched nerve and the limb function showed positive correlation (r=0.638,P <0.01).Nerve degen-eration appeared 1w after operation,the most significant myelin degeneration happened in the second week,began to recover in the fourth week.Conclusion:The MTR value of the distal portion of the stretched injury of sciatic nerve is positively re-lated with the function score of limbs,which can be used to monitor the change of nerve degeneration and regeneration after injury of nerve.%目的：探讨兔坐骨神经急性牵拉伤后不同时间点牵拉远段神经磁化传递率（MTR）与肢体功能的相关关系。方法：选取20只新西兰大白兔，右后肢为损伤侧，建立坐骨神经牵拉伤模型；左后肢为假手术侧。随机将实验兔分为两组，A 组（n＝12）于术前1天、术后1和3天以及1、2、4、6和8周分别行双侧后肢磁化传递 MRI 扫描，测量牵拉远段神经及假手术侧神经的 MTR 值；同时对实验兔的肢体功能进行展趾反射和改良 Tarlov 评分，分析术后1～8周 MTR 值与肢体功能的相关性；B 组（n＝8）于上述各时间点进行病理学检查。结果：牵拉远段神经的 MTR 值于损伤后1天明显降低，2周时达最低值，4～8周逐渐升高至正常水平，各时间点 MTR 值与假手术侧相比差异均有统计学意义（P ＜0．05）。牵拉伤后1天兔展趾反射及 Tarlov 评分降至最低；伤后1天～1周评分保持较低水平；伤后2～8周评分逐渐增高、肢体功能逐渐恢复。伤后1～8周牵拉远段神经 MTR 值与肢体功能评分呈正相关（r＝0．638，P ＜0．01）。病理检查显示术后1周神经开始退变，2周时髓鞘退变最显著，4周后开始恢复。结论：牵拉远段神经的 MTR 值与肢体功能评分呈正相关，提示 MTR值可用于监测伤后神经功能退变及再生的情况。
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