一种新型慢性压迫性颈脊髓症大鼠模型的建立

Establish of new type rat model of chronic compressive cervical myelopathy

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;P<0.05),脊髓后索的对比剂密度有显著性差异(98±5vs.88±6;P<0.05),后角内神经元也明显较少(23±8/mm2vs.27±6/mm2;P>0.05);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。

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 pathohistologica（lHE）/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/mm^2;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.