一种新型慢性压迫性颈脊髓症大鼠模型的建立

目的建立一种新型慢性压迫性颈脊髓症动物模型。方法 20只SD大鼠经颈后路手术、于C5～6水平椎板下植入吸水性聚氨酯胶片,植入体内逐渐吸水胀大,形成对脊髓的慢性持续压迫。术后6个月,进行体感诱发电位(SEP)、微焦点CT(Micro-CT)、组织学(H-E染色)和组织化学(LuxolFastBlue,LFB染色)等检测。结果 20只造模大鼠脊髓侧后方出现明显压迫性形态学改变,Micro-CT显示脊髓灰质和白质扭曲变形,14只出现SEP异常,其中波幅减低5例、潜伏期延长5例、二者均异常4例。SEP反应异常者与正常者组织学、组织化学比较,脊髓后索髓鞘染色显著减少(102±13vs.138±7;P0.05),脊髓后索的对比剂密度有显著性差异(98±5vs.88±6;P0.05),后角内神经元也明显较少(23±8/mm2vs.27±6/mm2;P0.05);造模大鼠脊髓出现基质海绵样变和静脉扩张、血管增生。结论该方法提供了一种操作方便、稳定性好、成功率高、评价指标完整的慢性压迫性脊髓症动物模型。

Establish of new type rat model of chronic compressive cervical myelopathy

Objective　To establish the new type chronic compressive cervical myelopathy on rat. Methods　Total 20 rats were operated with implantation of a water-absorbing polymer sheet in cervical spinal canal(C5～C6), which expanded gradually to induce chronic compression to the spinal cord. At 6 months after surgery, SEP, radiological (Micro-CT) and pathohistological（HE）/histochemistry（LFB） evaluations were done. Results　All 20 rats’ spinal cord showed significant morphological compressed deformity after chronic compression. It was also characterized by higher contrast intensity, distortion of gray matter and whiter matter under Micro-CT evaluations. 14 of 20 showed prolonged latency and/or decreased amplitude: decreased amplitude (n=5), prolonged latency (n=5), prolonged latency and decreased amplitude (n= 4). Compared with 6 rats with normal SEP responses, these 14 rats spinal cord showed significant less myelin staining in white matter (102±13 vs. 138±7; P＜0.05)，significant different regarding contrast medium density in posterior dorsal column(98±5 vs. 88±6; P＜0.05), and lower neuron density and cavitation in gray matter(23±8/mm2  vs. 27±6/mm2; P>0.05). Histological cystic cavitations, angiogenesis, and sinusoidal dilation of veins were noted in spinal cord with significant distortion after compression.　Conclusion　This new animal model provided convenient, intuitive, high succeed rate, multi-parameters, and stable tool for studying the mechanism of cervical spondylotic myelopathy.