红核脊髓运动诱发电位与脊髓损伤的关系

RALATIONSHIP BETWEEN GRADED SPINAL CORD INJURY AND RUBROSPINAL MEPS IN RATS

目的 :探讨一种可以敏感地反映脊髓损伤程度的客观、定量的电生理学指标。方法 :采用Wrathall等人描述的重力损伤法制备大鼠脊髓胸段 (T8)分级损伤模型 ,通过测量损伤动物红核 -脊髓运动诱发电位 (MEPs)的变化 ,并与动物运动行为和组织形态学检查结果进行比较 ,分析红核 脊髓MEPs与脊髓分级损伤的关系。结果 :在给予红核刺激后 ,假损伤组红核 脊髓MEPs出现 5～ 7个正波和 4～ 5个负波 ,峰 峰总幅度值 (简称总峰值 )为(195 .2 5± 34.35 ) μV ,峰潜伏时为 (1.5 7± 0 .15 )ms。随损伤程度加大 ,总峰值明显减少 ,而峰潜伏时明显延长。红核 脊髓MEPs总峰值与观察期末的BBB评分 (r =0 .79)以及损伤中心处的残余面积 (r =0 .87)显著相关 ;峰潜伏时与观察期末的BBB评分 (r=- 0 .88)以及损伤中心处的残余面积 (r =- 0 .86 )也有显著的相关性。结论 :红核 脊髓MEPs总峰值和峰潜伏时两项指标可以敏感地反映脊髓分级损伤程度、运动功能和形态学情况 ,是监测胸段脊髓损伤程度的客观、定量、精细的电生理指标。

Aim: To explove an accurate neurophysiological technique that demonstrates small functional differences after spinal cord injury and assesses therapeutic interventions. Methods: A modified weight drop(WD) technique was used at T8 in rats to build graded spinal cord injury model. Rubrospinal MEPs were recorded at T13 epidurally to monitor spinal cord function in end week 4 after graded spinal cord injury .The efficacy of this techniques to monitor spinal cord function was compared to BBB locomotor rating scale and histologic evaluation. Results: A characteristic peak complex of rubrospinal MEPs in sham-operated group consisted of 5～7 positive waves and 4～5 negative waves emerging after red nucleus stimulation. The summed peak to peak amplitude(for practical reasons,called peak amplitude) was (195.25±34.35)μV and decreased following spinal cord injury. The latency of the first peak (positive wave) was (1.57±0.15)ms and prolonged following spinal cord injury. Significant Linear relationship existed between the peak amplitude and the BBB scores(r=0.79)and between the peak amplitude and the residual matter obtained from the section with maximum tissue damage(r=0.87). The close relationship between the latency of the first peak and the BBB scores(r=-0.88)and between the latency of the first peak and residual matter (r=-0.86) were observed. Conclusion: Amplitudes and latencies of rubrospinal MEPs are very valuable parameters to demonstrate small function differences. Rubrospinal MEPs can be used as a reliable measure for motor function prognosis after spinal cord injury.