应用大脑皮层诱发电位建立精确分级脊髓损伤模型

目的 建立脊髓损伤精确分级动物模型.方法 自行设计一种犬的运动-静止压迫型脊髓损伤模型,以大脑皮层诱发电位(CSEP)和不同压迫时间为参数,以T13横突连线为中心,安装大小为0.6 cm×1.0 cm的加压阀,以0.2 mm/min速度压迫脊髓,同时持续性CSEP监测,随压迫深度加深,CSEP波幅不断压低,当波幅下降达基础值的50%时停止下压,继续维持压迫,将20只杂种犬随机分为三组:A组(n=8):脊髓继续受压30 min;B组(n=8):脊髓继续受压180 min;C组(n=4):为对照组,脊髓显露后不损伤.观察电生理学、组织病理学、功能恢复及MRI变化.结果 两组脊髓组织学均有损害、MRI显示两组均有脊髓受压性改变,按照Aiith法计算A、B组的脊髓白质残留面积百分比和MRI脊髓变性空洞区最大横面积百分比,差异均有统计学意义(P<0.05);A组CSEP逐渐恢复达基线的76%,B组CSEP无恢复,C组一直无变化;脊髓受压早期两组均有后肢功能障碍,按照改良的Tarlov测定法和运动能力法评估A、B两组,差异有统计学意义(P<0.05).结论 以CSEP和不同压迫时间为参数,能够建立不同损伤程度的可重复性强的分级脊髓损伤模型.

A new animal model for accurately grading spinal cord injury using cortex somatosensory evoked potentials

Objective To establish an animal model for accurately grading different degrees of spinal cord injury. Methods Eight dogs underwent sustained compression on spinal cord for 30 minutes in group A and another 8 for 180 minutes in group B using a self-designed device for weight-loading com-pression on spinal cord. Cortex somatosensory evoked potentials (CSEP) were monitored during all the pro-cedures of making the model. Functional motion recovery was judged throughout all the 28 days using the Combined Behavioral Score (CBS) and modified Tarlov system. The volume of the lesion to the tissue was assessed with magnetic imaging and histological analysis. Results The CSEP amplitude in group A re-covered gradually,but there was no recovery in group B. The volume of lesion to the tissue in group A was significantly smaller than that in group B (P<0.05). The behavior improvement in group A was significantly greater than that in group B (P<0.05). Conclusion An ideal,reliable and duplicable animal model can be established for grading spinal cord injury using the 2 parameters of CSEP and time.