球囊注射压迫法建立山羊颈脊髓慢性压迫模型

目的 验证一种新型颈脊髓慢性压迫动物模型建立方法的可行性.方法 选取18只崇明山羊,随机分为实验组(15只)和对照组(3只).通过前路手术将球囊压迫装置固定在C3椎体内,实验组术后每周经皮向注射阀注射0.1 ml造影剂,使球囊缓慢膨胀,对颈脊髓产生慢性压迫；对照组放置压迫装置后即刻取出,术后每周仅经皮穿刺但不注射造影剂.每4周采用Tarlov评分法对动物进行行为学评价,在全麻下进行颈椎X线、CT、MRI检查,并处死2只取压迫节段脊髓进行病理学观察.结果 对照组各时间点Tarlov评分均为5分.实验组术后4周(n=13)Tarlov评分不变；术后8周时(n=11)有2只Tarlov评分为4分,9只5分；术后12周时(n＝9)有3只Tarlov评分为2分,4只3分,2只4分.影像学检查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,随着时间推移,脊髓逐渐受压.病理学检查显示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数量减少,胞体周围间隙增大,白质轻度脱髓鞘,部分轴突空泡变性；术后12周白质出现片状脱髓鞘区和空泡变性.结论 术后实验动物行为学、影像学和组织学检查符合慢性压迫性颈脊髓病特点,说明新型球囊注射压迫系统可以辅助建立稳定、可靠的慢性颈脊髓压迫动物模型.

A goat model of chronic cervical spinal cord compression by balloon compression system

ObjectiveTo establish a new animal model of chronic cervical compressive myelopathy and to assess its feasibility. MethodsEighteen Chongming goats were divided into two groups: control group (n=3) and experimental group (n=15). The balloon was placed into the C3 intervertebral space by anterior approach operation, and the syringe valve was fixed subcutaneously. Contrast agent was injected percutaneously into the valve (0.1 ml/week) to inflate the balloon progressively to produce chronic compression. In the control group, the balloon compression system was placed and immediately removed; percutaneous puncture was performed each week without injecting anything. The Tarlov scores were assessed in each group every four weeks. The goats underwent X-ray, CT and MRI under general anesthesia every four weeks. The spinal cord specimens were pathologically examined at test level at the end of experiment. ResultsThe Tarlov scores were 5 (normal) at all time points in the control group. Tarlov scores were not changed in the experimental group four weeks after surgery (n=13); at eight weeks after surgery (n=11) the Tarlov scores were 4 in 2 goats and 5 in 9 goats; and at twelve weeks after surgery (n=9) the Tarlov scores were 2 in 3 goats, 3 in 4 goats and 4 in 2 goats. The balloon compression system was stable in the experimental group. Radiological findings showed that the cervical spinal cord compressed progressively in the experimental group as time went by, and those in the control group underwent no noticeable change. Pathological examination showed neuronatrophy, increased gap around the neurons, mild demyelinated and vacuolar degeneration in the experimental group at eight weeks after surgery, and these changes were deteriorated twelve weeks after surgery. There were no noticeable pathological changes in the control group and four weeks after surgery in the experimental group. ConclusionThe postoperative behavior, radiological and pathological findings of the animals consist with the character of chronic cervical compressive myelopathy, indicating that the balloon compression system in the present study can be used to establish a reliable and stable animal model of chronic cervical spinal cord compression.