目的 探讨胫后神经F波对大鼠不同程度的坐骨神经损伤(SNI)动物模型评估作用.方法 18只SPF级成年SD大鼠随机区组法分为Sham组(假手术组,6只)、SNI组(坐骨神经损伤组,12只).Sham组只行坐骨神经分离术,不进行夹压.SNI组分为SNI-A组[小号(10 mm × 18 mm)动脉夹夹压组,6只]、SNI-B组[大号(17 mm ×48 mm)动脉夹夹压组,6只].各组观察急性期F波波形变化2 h,记录术前、术后2 h、2 d和7 d F波,术前、术后2 d和7 d评估坐骨神经功能指数(SFI).各组术后7 d取大鼠坐骨神经标本行苏木精-伊红染色(HE)切片和电镜切片.结果 SNI-A组和SNI-B组所有大鼠坐骨神经被夹压后均即刻出现F波消失.SNI-A组术后2 h、2 d和7 d波幅[(0.0±0.0)、(18.7±13.4)、(54.2±17.4)μV]明显低于术前[(113.2±28.9)μV],差异有统计学意义(t=9.591、9.202、11.775,P 均＜0.05);SNI-B 组术后 2 h、2 d 和 7 d 波幅[(0.0±0.0)、(3.0 ±2.1)、(6.13±4.3)μV]明显低于术前[(123.6±14.9)μV],差异有统计学意义(t=8.269、8.167、7.928,P 均＜0.05).SNI-A 组术后 2 d 和 7 d 潜伏期[(11.7±2.0)、(10.2±0.5)ms]明显长于术前[(8.9±0.8)ms],差异有统计学意义(t=4.621、5.363,P均＜0.05).SNI-A组术后2 d和7 d SFI(-59.0±4.4、-51.6±3.5)明显低于术前(-4.3±1.0),差异有统计学意义(t=29.490、32.049,P 均＜0.05);SNI-B 组术后 2 d 和 7 d SFI(-80.3±3.2、-75.0±6.8)明显低于术前(-4.8±1.4),差异有统计学意义(t=23.056、24.692,P均＜0.05).HE切片Sham组神经外膜、轴突正常;SNI-A组神经外膜完整,轴突小部分断裂;SNI-B组神经外膜完整,轴突明显断裂.电镜Sham组髓鞘板层致密,轴突无空泡样变;SNI-A组髓鞘板层轻微分离,轴突少数空泡样变;SNI-B组髓鞘板层明显分离,轴突明显空泡样变.结论 大鼠胫后神经F波对评估坐骨神经损伤非常敏感;小号(10 mm × 18 mm)和大号(17 mm ×48 mm)动脉夹夹压法可以建立Sunderland Ⅱ和Ⅲ度不同程度的坐骨神经损伤的大鼠动物模型.
Evaluation effect of F-wave in rat models with different degrees of sciatic nerve injury
Objective To explore the evaluation effect of posterior tibial nerve F-wave in different degrees of sciatic nerve injury(SNI)animal models of rats.Methods Totally,18 adult SD rats were ran-domly divided into sham surgery group(n=6)and SNI group(n=12).The Sham group only underwent sciatic nerve separation surgery without compression.The SNI group was divided into SNI-A subgroup[small size(10 mm × 18 mm)arterial clamp pressure subgroup,n=6],SNI-B subgroup[large(17 mm × 48 mm)arterial clamp pressure subgroup,n=6].F-wave was observed for 2 h in each group during the a-cute phase.F-wave was recorded preoperatively and 2 h,2 days and 7 days postoperatively.The sciatic functional index was assessed preoperatively and 2 days and 7 days postoperatively.The sciatic nerve sam-ples were taken from all the rats 7 days postoperation for hematoxylin-eosin(HE)staining and electron mi-croscopy.Results F-waves disappeared immediately after sciatic nerve clamped in SNI-A and SNI-B subgroups.The amplitudes of F-waves in the SNI-A subgroup at 2 h,2 days,and 7 days postoperation[(0.0±0.0),(18.7±13.4),(54.2±17.4)μV]were significantly lower than those preoperation[(113.2±28.9)μV,t=9.591,9.202,11.775,P＜0.05)].The amplitudes of F-vaves in the SNI-B subgroup at 2 h,2 days and 7 days postoperation[(0.0±0.0),(3.0±2.1),(6.13±4.3)μV]were significantly lower than those preoperation[(123.6±14.9)μV,t=8.269,8.167,7.928,P＜0.05)].The latency of F-wavels in the SNI-A subgroup at 2 days and 7 days postoperation[(11.7±2.0),(10.2± 0.5)ms]were significantly longer than that preoperation[(8.9±0.8)ms,t=4.621,5.363,P＜0.05)].The sciatic functional index(SFI)in the SNI-A subgroup at 2 days and 7 days postoperation(-59.0±4.4,-51.6±3.5)was significantly lower than that preoperation(-4.3±1.0,t=29.490,32.049,P＜0.05).The SFI in the SNI-B subgroup at 2 days and 7 days postoperation(-80.3±3.2,-75.0±6.8)was significantly lower than that preoperation(-4.8±1.4,t=23.056,24.692,P＜0.05).HE staining showed that the epineurium and axon were normal in the Sham group.The epineurium was intact and the axon was partially broken in the SNI-A subgroup.The epineurium was intact and the ax-on was obviously broken in the SNI-B subgroup.Electron microscopy showed that the myelin lamina was dense and axon was not vacuolated in the Sham group.The myelin lamina was slightly separated and axon showed a few vacuolar degeneration in the SNI-A subgroup.The myelin lamina was separated and the axon was vacuolated in the SNI-B subgroup.Conclusion The F-waves of the posterior tibial nerve in rats can highly sensitively evaluate SCI.The methods of mall size(10 mm × 18 mm)and large size(7 mm × 48 mm)arterial clamp pressure can establish Sunderland Ⅱ and Ⅲ different degrees SCI animal models of rats,respectively.
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