犬椎间盘脱出模型的建立及其脊髓微循环与组织学变化观察

目的通过外科手术方法建立犬椎间盘脱出模型,观察造模前后脊髓微循环与组织学变化,为研究椎间盘病脊髓的病理和治疗机理积累资料。方法健康成年犬随机分为正常对照组和模型组。半椎板切除术暴露L1段脊髓后,将6Fr硅胶双腔导尿管球囊放置在T12-T13脊髓左下方处,向导管内注入约0.5 mL的碘海醇使球囊内膨胀压迫脊髓,模拟由于髓核脱出引起的椎间盘脱出症;利用激光散斑血流监控系统实时监测压迫前后L1段脊髓血流量(spinal cord blood flow,SCBF)变化;术后14 d观察压迫部位脊髓组织学形态。结果模型组两侧后肢运动机能极显著下降(P0.01),L1段脊髓血流量显著下降(P0.05);与正常组相比,模型组脊髓白质出现空泡化,灰质腹角正常神经元数量极显著下降(P0.01)。结论球囊压迫法可成功建立犬椎间盘脱出瘫痪模型,并观察到脊髓局部微循环障碍和形态学变化,可作为评价针灸等治疗效果和机理的模型。

Establishment of models with intervertebral disc extrusion in dogs and observation of the change in the spinal cord microcirculation and histology

Objective To establish a canine model of intervertebral disc extrusion by surgery and observe the histological and microcirculatory changes of the spinal cord, in order to accumulate data for studies on the pathology and mechanism of treatment for intervertebral disc extrusion. Methods Normal healthy adult dogs were divided randomly into two groups: normal control group and model group. To simulate the intervertebral disc extrusion caused by spinal cord compression, 6Fr double lumen catheter with ballon was inserted into the spinal cord T₁₂-T₁₃ and filled with about 5 mL Iohexol after the exposure of spinal cord L₁ by hemilaminectomy. The spinal cord blood flow (SCBF) at the L1 level before and after compression was measured by laser-Doppler flowmetry. Morphological changes of the compressed spinal cord at 14 days after compression was examined by histopathology.Results The (Texas spinal cord injury score) (TSCIS) scores of the motor function of bilateral hind limbs were highly significantly decreased (P<0.01). The blood flow of spinal cord at the L1 level was significantly decreased (P<0.05) after compression than that before. Compared with the normal control group, the model group showed abnormal vacuolization in the white matter and the number of normal neurons in the ventral horn of gray matter was significantly lower(P<0.01). Conclusions Our findings demonstrate that canine models of intervertebral disc extrusion can be successfully established by balloon catheter compression, showing local impairment of microcirculation and histological changes in the spinal cord. This canine model may provide a useful model for evaluation of therapeutic effects of acupuncture and for mechanism studies.