慢性压迫性颈脊髓病山羊模型的建立与评估

Establishment and Evaluation of Goat Chronic Cervical Spinal Cord Compression Model

目的验证一种慢性压迫性颈脊髓病动物模型的建立方法,并评估其可行性。方法选取12只崇明山羊(雌性),随机分为实验组(9只)和对照组(3只)。通过颈椎前路手术将一种新型脊髓压迫装置固定在C3椎体内,实验组术后每周经外置注射器向球囊内注射0.1mL造影剂,使球囊逐渐膨胀,从而对实验动物脊髓造成持续性压迫;对照组安装压迫装置后,每周仅经皮穿刺但不注射造影剂。造模后4周、8周、12周采用Tarlov评分法对实验动物进行脊髓运动功能评分,颈椎行X线、CT检查,并在不同时间点分别处死2只实验动物,取压迫节段脊髓切片进行病理学检查。结果对照组各时间点Tarlov评分均为5分。实验组术后4周(n=9)Tarlov评分不变;术后8周时(n=7)Tarlov评分3只4分,4只5分;术后12周时(n=5)Tarlov评分3只3分,2只2分。影像学显示对照组脊髓未见明显异常;实验组球囊压迫系统表现稳定,随着每周不断注入造影剂后球囊增大,脊髓逐渐受压。病理学检查对照组未见明显异常。实验组术后4周未见明显异常;术后8周受压节段脊髓前角内神经元细胞变性,胞体萎缩变小,但数量未见明显减少,部分白质出现轻度脱髓鞘改变,部分轴突出现空泡样变性;术后12周,神经元细胞变性明显,部分出现坏死,细胞核固缩,白质弥漫性脱髓鞘,轴突空泡样变性明显。结论建模术后实验动物脊髓运动功能、影像学和病理学检查结果均符合慢性压迫性颈脊髓病特点,说明该新型脊髓压迫系统可以建立稳定的、可重复的慢性脊髓压迫动物模型。

Objective To develop a new animal model of chronic cervical compressive myelopathy and to assess its feasibility.Methods Twelve Chong-ming goats were divided into two groups：control group（n=3）and experimental group（n=9）.A new spinal cord compression device was placed into the C3 vertebral body by anterior approach operation,and the syringe valve was fixed subcutaneously.In the experimental grouP〈0.1 ml of contrast agent were injected into the balloon every week after operation,which gradually expanded the balloon,resulting in the continuous compression to the experimental animal spinal cord.In the control group,after the implanation of compression device,we only punctured with the needle but did not inject the contrast agent each week.In the 4 th week,8 th week and 12 th week,the Tarlov scoring method was used to grade the spinal motor function of the experimental animals,and the cervical vertebral X-ray and CT examination were performed,and 2 experimental animals were euthanized at different time points for pathological examination of the compression spinal section.Results The Tarlov scores were 5（normal）at all time points in the control group.Tarlov scores were not changed in the experimental group in the 4 th week（n=9）.In the 8 th week（n=7）the Tarlov score was 4 in 3 goats and 5 in 4 goats.In the 12 th week（n=5）,the Tarlov score was 3 in 3 goats,2 in 2 goats.Imaging showed no obvious abnormalities in the spinal cord.The balloon compression system of the experimental group was stable,and the spinal cord was gradually compressed with the enlargement of the balloon after the continuous injection of the contrast agent.There was no obvious abnormality in the pathological examination.No obvious abnormalities were observed in the experimental group at the 4 th week.In the 8 th week,we found the spinal cord ventral horn neurons degeneration,decreased cell body size,but not seen obvious decrease of neuron number.Some white matter appeared mild demyelination changes.Some axises showed cavitation degeneration.In the 12 th week,the neuronal cell degeneration was obvious.Necrosis,degeneration of nucleus,the diffuse demyelination of white matter,and the obvious degeneration of axonal vacuolar were found.Conclusion Modeling experimental animal postoperative spinal movement function,imaging and pathological examination results in chronic compression characteristic of cervical myelopathy show that the new type of spinal cord compression system can establish a stable and repeatable chronic animal model of spinal cord compression.