F波评估兔不同程度永久性腰髓缺血损伤动物模型的价值

Value of F-wave in evaluating lumbar spinal cord injury in rabbit models of different levels of permanent spinal cord ischemia

目的探讨兔胫后神经F波对不同水平永久性腰髓缺血动物模型的评估作用。方法 30只新西兰大白兔采用完全随机方式分为6组,1组为对照组,其余5组为实验组。对照组(n=5)用于确定最佳刺激强度,并用于排除麻醉和手术对F波的影响,实验组(n=5)分别结扎左肾动脉和动脉分叉间不同水平的腰动脉,腰动脉结扎后2 h和2 d记录F波,分别在麻醉清醒后和手术后2 d进行运动功能评分,分析实验各组术后2 h F波波幅变化与下肢运动功能的相关性,2 d后取缺血中心区标本进行HE染色,观察缺血区病理变化。结果 F波的波幅在1根组和2根组结扎前后没有明显的变化(P>0.05),结扎前后不同时间点经方差分析,差异均无统计学意义(P>0.05),;结扎3根组、4根组和5根组血管后的F波的波幅下降,各组结扎前后不同时间点波幅经方差分析,差异均有统计学意义(P<0.05);F波的潜伏期在1根组和2根组结扎前后没有明显的变化(P>0.05),在3根组、4根组和5根组随着缺血程度的增加逐渐延长,各组潜伏期结扎前后不同时间点经方差分析,差异均无统计学意义(P>0.05)。结论兔下肢胫后神经F波的潜伏期不能量化反映腰髓缺血损伤程度,但严重缺血后潜伏期也可延长;F波波幅能够反映腰髓缺血损伤程度并且能够预测脊髓的功能。

Objective To investigate the evaluating effect of F-wave of posterior tibial nerve of rabbits on the different levels of lumbar spinal cord ischemic injury in animal models. Methods Thirty New Zealand white rabbits were divided into 6 groups by complete randomization, with one of them as the control group, the other five groups as experimental group. The control group （n=5） was used to determine the best stimulus intensity and eliminate the influ- ence of anesthesia and surgery on F-wave; the rats in the five experimental groups （n=5） were ligated in the different lev- els of lumbar arteries in the left renal artery and arterial bifurcation. The changes of F-wave 2 h and 2 d after ligation were recorded. The motor fimctions were scored after anesthesia recovery and 2 d after operation. The correlation be- tween the changes of F-wave amplitude 2 h after operation in the experimental groups and lower limb motor function was analyzed. Specimens in the central ischemic region were collected for HE staining to observe the pathological chang- es in ischemic area. Results There was no significant change （P〉0.05） in the F-wave amplitude before and after liga- tion of one or two lumbar arteries, and analysis of variance at different time points before and after ligation showed no statistically significant difference （P〉0.05）. The F-wave amplitude was decreased when three or four or even five lumbar arteries were ligated, and analysis of variance at different time points in each groups before and after ligation showed sta- tistically significant difference （P〈0.05）. The latency of F-wave has no significant change （P〉0.05） before and after liga- tion of one or two lumbar arteries, but it was gradually prolonged with the increase of the degree of ischemia when three or four or five lumbar arteries were ligated. Analysis of variance at different time points in each groups showed no statis- tically significant difference in the latency of F-wave （P〉0.05）. Conclusion The lumbar spinal cord ischemic injury cannot be accurately quantified through the latency of F-wave in posterior tibial nerve of rabbits, but the latency of F-wave would be extended when spinal cord ischemia was severe. The amplitude of F-wave can reflect the degree of lumbar spinal cord injury and predict the function of the spinal cord.