Abstract:

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.

Key words: Cervical myelopathy, Chronic compression, Animal model, Rat