Establish of new type rat model of chronic compressive cervical myelopathy

Abstract

目的 建立一種新型慢性壓迫性頸脊髓癥動物模型.方法 20只SD大鼠經頸后路手術、于C5～6水平椎板下植入吸水性聚氨酯膠片,植入體內逐漸吸水脹大,形成對脊髓的慢性持續壓迫.術后6個月,進行體感誘發電位(SEP)、微焦點CT(Micro-CT)、組織學(H-E染色)和組織化學(Luxol Fast Blue,LFB染色)等檢測.結果 20只造模大鼠脊髓側后方出現明顯壓迫性形態學改變,Micro-CT顯示脊髓灰質和白質扭曲變形,14只出現SEP異常,其中波幅減低5例、潛伏期延長5例、二者均異常4例.SEP反應異常者與正常者組織學、組織化學比較,脊髓后索髓鞘染色顯著減少(102±13 vs.138±7;P<0.05),脊髓后索的對比劑密度有顯著性差異(98±5 vs.88±6;P<0.05),后角內神經元也明顯較少(23±8/mm2vs.27±6/mm2;P>0.05);造模大鼠脊髓出現基質海綿樣變和靜脈擴張、血管增生.結論 該方法提供了一種操作方便、穩定性好、成功率高、評價指標完整的慢性壓迫性脊髓癥動物模型. 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/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.