大鼠骶丛根性撕脱伤模型的建立

Establishment of an animal model of sacral nerve root avulsion in rats

目的建立大鼠骶丛撕脱伤模型并评价其有效性。方法选用20只成年SD大鼠，雌雄不限，不打开椎板，在神经孔外撕断右侧L4-6神经根，左侧为对照侧。术后观察各组大鼠的存活情况，对受试大鼠进行受试鼠行为学运动（Basso-Beattie-Bresnahan，BBB）评分。并对其进行体感诱发电位（SEP）及双侧股二头肌、小腿三头肌及胫前肌刺激电位检测，辣根过氧化酶（HRP）逆行示踪，双侧股二头肌、小腿三头肌及胫前肌称重及肌肉横截面行双侧对比研究，以评价造模效果。结果（1）一般情况：19只大鼠存活，1只大鼠死亡，存活率为95．0％。实验大鼠BBB评分为（10．78±3．15）分，而正常大鼠为21分；（2）SEP检测：17只大鼠患肢未在双侧大脑皮层检测到SEP，造模成功率为89．5％；（3）HRP示踪：2只大鼠脊髓L1-4节段内可见阳性反应，17例阴性，造模成功率为89．5％；（4）双侧股二头肌、小腿三头肌及胫前肌称重及肌肉横截面对比，差异有统计学意义；（5）电镜检测撕脱侧肌肉出现萎缩、细胞核中间移位及出现肌卫星细胞等失神经支配征象。结论通过大鼠椎管外撕脱L4-6造模，是建立大鼠骶丛撕脱伤模型的一种可行而理想的方法。

Objective To establish an animal model of sacral nerve root avulsion in rats and evaluate its efficiency. Methods A total of 20 adult SD rats （either sex） were chosen at random to establish the sacral nerve root avulsion model by avulsing the right L4-6 nerve roots out of intervertebral foramina without lamineetomy. The left side was set as control group. The models were evaluated in aspects of survival rate, Basso-Beattie-Bresnahan （BBB） scores, somatosensory evoked potential （SEP）, horse radish peroxidase （HRP） tracing, bilateral weight and cross section area （CSA） of muscle biceps femoris, fiber of triceps surae and anterior tibial muscle. Results Of all, 19 rats were survived but one died, with survival rate of 95.0%. The BBB score was （10.78 ±3.15） points in experimental group and 21 points in control group. The success rate of establishing animal model was 89.5% ,for there detected no SEP in bilateral cerebral cortex of the wounded extremity of 17 rats. HRP showed positive reaction in the spinal segment of L1-4 in two rats but negative in 17, with success rate of 89.5%. There was statistical difference in aspects of weight and muscle fiber CSA of double biceps femoris, triceps surae and anterior tibial muscle between experimental group and control group. Electron microscope found denervation changes including muscle fiber atrophy, nucleus shifting to center and muscle satellite cell. Conclusion Avulsion of L4.6 sacral nerve root out of vertebral canal is a feasible and ideal method to establish the avulsion model of sacral nerve root injury in rats.