小鼠脊髓损伤半切模型的建立及评价

Establishment and evaluation of mouse spinal cord hemi-section injury model

目的建立一种稳定可靠、重复性强的脊髓损伤半切动物模型,模拟人类脊髓半切伤,为后期脊髓损伤的治疗研究提供可靠的动物模型。方法 60只健康昆明小鼠随机分为手术组和假手术组。实验小鼠麻醉后俯卧位固定,以T10胸椎棘突为中心,暴露T9~11棘突和椎板;在体式显微镜下,咬除T10棘突及椎板,暴露该阶段脊髓;用虹膜剪尖端将脊髓半切至脊髓后正中静脉右缘。于造模后1d、3d、5d、1w、2w、3w,采用双盲BMS评分法,评价各组小鼠后肢运动功能。并取损伤局部脊髓组织进行结晶紫染色、Caspase3免疫组织化学染色及超微结构检测,以观察脊髓损伤后的组织学变化。结果手术组实验动物均表现出损伤侧后肢瘫痪,BMS评分低于7分;脊髓损伤局部形态学观察显示该方法能很好地实现脊髓半横切。结论小鼠T10脊髓损伤半切模型建立成功,死亡率低,可重复性强。

Objective To establish a stable,reliable and well repeatable animal model of spinal cord hemi-section injury in mice which can mimic human spinal cord hemi-section injury and provide a reliable animal model for study on therapy of spinal cord injury in the later stage.Methods 60 healthy Kunming mice were randomly divided into operation group and sham-operation group.The experimental mice were fixed in the prone position after anesthesia,then the T9-11 spinous processes and lamina were exposed as centered on the T10 thoracic spinous processes.Under the stereo microscope,the T10 spinous processes and lamina were removed thus the spinal cord was exposed.Then a hemi-section of the right hemi-cord at T10 to the right margin of the median vein behind the spinal cord was performed with the tip of iris scissors.The Basso Mouse Scale(BMS)scoring method for locomotion was used to assess the degree of the hind limbs’motor dysfunction at 1d,3d,5d,1w,2w,3w after establishment of spinal cord hemi-section injury model.And then the injured spinal cord was taken out for crystal violet staining,Caspase 3 immunohistochemical staining and ultrastructural analysis to observe the morphological changes after spinal cord injury.Results In the experimental group,the hind limbs of all injured mice were under paralysis along with the injured side of the spine cord.BMS score was less than 7 points.The local morphological observation showed that this method met the criteria of spinal cord hemi-section.Conclusion The T10 spinal cord hemi-section injury model in mice was successfully established,which had low mortality and high repeatability.