绵羊慢性压迫性颈脊髓病动物模型的建立及评估

Establishment and evaluation of a new experimental animal model of chronic cervical compressive myelopathy

中文关键词:  慢性压迫性颈脊髓病  绵羊  动物模型  球囊

英文关键词:Chronic cervical compressive myelopathy  Sheep  Animal model  Balloon

中文摘要:

  【摘要】 目的：探讨颈脊髓慢性压迫动物模型的建立方法及可行性评估。方法：将9只绵羊分为对照组（Ａ组）、1个月组（Ｂ组）和3个月组（Ｃ组）。经颈前路手术将新型注射压迫系统的致压球囊置入C4/5椎间隙并固定，将注射阀埋于颈后皮下。Ａ组术后不注射碘海醇，Ｂ、Ｃ组术后每周经皮向注射阀注射0.1ml碘海醇，使球囊缓慢膨胀，对颈脊髓产生慢性压迫。每4周于全麻下行颈椎X线、CT和MRI检查。每次注射造影剂后和检查前后用Tarlov评分法对动物进行行为学评价。终止观察时取压迫节段脊髓进行病理观察及电镜观察超微结构变化。应用单因素方差分析评估不同组实验动物行为学的差异，用Pearson相关系数分析各观测参数的相关性。结果：A组各时间点Tarlov 评分均为5分。B组及C组每次注射造影剂前后Ｔａｒｌｏｖ评分不变。终止观察时B组实验动物平均椎管侵占率为54.6%，Tarlov评分1只4分，2只5分；C组实验动物平均椎管侵占率67.6%，Tarlov评分1只2分，2只3分。肉眼可见B组受压节段脊髓变扁，C组明显凹陷；病理学检查见B组受压节段脊髓前角内神经元数量减少，胞体周围间隙增大，尼氏体减少，白质轻度脱髓鞘，部分轴突空泡变性；C组白质出现片状脱髓鞘区和空泡变性，灰质内多量神经元变性，可见核固缩、尼氏体减少或消失。电镜下B组神经元胞质内粗面内质网轻度扩张，部分线粒体肿胀，轴突空泡变性，形态不规则，髓鞘松解，部分轴突髓鞘脱失；C组神经元可见胞膜崩解，核固缩，粗面内质网明显扩张，核糖体脱失，线粒体广泛空泡变性，髓鞘崩解，轴突肿胀，基质致密，部分轴突消失。Ａ组未见异常组织学改变。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，新型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。

英文摘要:

  【Abstract】　Objective：To explore a new experimental animal model of chronic cervical compressive myelopathy．Method: Nine small-tailed sheep were divided into three groups:control group（A），1-month group（B） and 3-month group（C）．The balloon was inserted into the C4/5 intervertebral space by anterior approach，and the syringe valve was fixed subcutaneously．Contrast agent was injected into the valve 0.1ml/week percutaneously．The sheep underent X-ray，CT and MRI under general anesthesia every four weeks．The Tarlov scores were assessed in each group．The spinal cord specimens at test level wｅｒｅ examined by optical microscope and transmission electron microscope at the end of experiment．ANOVA was applied to assess the difference of Tarlov scores among three groups, and the correlation of the parameters was analyzed by Pearson method．Result:The final radiological findings showed that the average spinal canal encroachment rate was 54.6% in group B and 67.6% in group C．Ｔｈｅｒｅ　ｗｅｒｅ　ｎｏ　Ｔａｒｌｏｖ　ｃｈａｎｇｅｓ　ａｆｔｅｒ　ａｎｄ　ｂｅｆｏｒｅ　ｐｅｒｃｕｔａｎｅｏｕｓｌｙ　ｉｎｊｅｃｔｅｄ．The final Tarlov score was 5（normal）in all the sheep of group A，5 in 2 sheep and 4 in 1 sheep of group B，3 in 2 sheep and 2 in 1 sheep in group C．The gross appearance of spinal cord in test level was normal in group A，flat in group B，and depressed in group C．The pathological examination showed neuronatrophy，increased gap around the neurons，reduction of Nissl body，mild demyelinated and vacuolar degeneration in group B，while more remarkably in group C．The ultrastructural pathology showed mild degeneration of neurons，slight expansion of rough endoplasmic reticulum，mitochondrial swelling，myelin sheath release，demyelination and vacuolar degeneration of some axons in group B，while more remarkably in group C，which presented with neuronal cell membrane breakdown，nuclear pyknosis，ribosomal depigmentation and disappearance of some axons．Conclusion:The postoperative behavior，radiological results and histological examination are in accordance with the character of chronic cervical compressive myelopathy， which can be used to establish a reliable and stable animal model of chronic cervical compressive myelopathy.