C_(3-4)神经根转位修复C_(5-6)神经后颈髓神经元及轴突的可塑性变化

CHANGE IN PLASTICITY OF CERVICAL CORD NEURONS AND AXONS AFTER C_(3-4) NERVE ROOT TRANSPOSITION FOR C_(5-6) NERVE REPAIR

目的研究颈3-4(C_(3-4))神经根转位修复颈5-6(C_(5-6))神经后,颈段脊髓神经元及轴突的可塑性变化。方法取健康成年SD大鼠90只,随机分成正常组、对照组和实验组,各30例。正常组不进行手术;对照组将右侧C_(3-4)神经根在根干交界处切断,C_(5-6)神经根在出椎间孔处切断,不进行吻合;实验组在对照组基础上将C3神经根与C5神经根吻合,C4神经根与C6神经根吻合。分别饲养1、3、6个月进行取材,对颈段脊髓和神经纤维进行大体观察、苏木精-伊红(HE)染色、免疫组化染色观察。结果脊髓HE染色显示,术后6个月时前角运动神经元计数为正常组(35.11±1.53)>实验组(27.45±1.86)>对照组(25.36±1.87)(F=4.73,P<0.05)。脊髓前角染色显示,实验组(23.56±3.18)与对照组(23.08±2.86)术后的免疫阳性运动神经元计数均减少,至术后6个月时逐渐增多并趋于稳定,均略低于正常组(25.53±3.42),差异无统计学意义(F=2.13,P>0.05)。吻合口以近神经纤维染色显示,术后6个月时实验组运动纤维计数(45.97±7.76)高于正常组(38.15±5.65)和对照组(37.36±6.10)(F=5.92,P<0.05)。结论 C_(3-4)神经根转位修复C_(5-6)神经后,C_(3-4)节段发生可塑性变化,脊髓前角运动神经元和大量有髓神经纤维再生,神经功能得到较好恢复。

Objective To investigate the change in plasticity of cervical cord neurons and axons after C 3-4 nerve root transposition for C 5-6 nerve repair. Methods A total of 90 healthy adult Sprague-Dawley rats were randomly divided into normal group, control group, and experimental group. The rats in the normal group were not given surgery; as for the rats in the control group, the right C 3-4 nerve root was cut off at their junction, and the C 5-6 nerve root was cut off at the intervertebral foramen, without anastomosis; as for the rats in the experimental group, the C 3 nerve root was anastomosed with the C 5 nerve root, and the C 4 nerve root was anastomosed with the C 6 nerve root, in addition to the treatment in the control group. Related samples were collected at 1,3, and 6 months after surgery, and gross observation, HE staining, and immunohistochemical staining were performed for the cervical cord and nerve fibers. Results HE staining of the spinal cord showed that at 6 months after surgery, the normal group had the highest number of motor neurons in the anterior horn （35.11±1.53）, followed by the experimental group （27.45±1.86） and the control group （25.36±1.87）, and there was a significant difference between the three groups （ F =4.73, P 〈0.05）. Choline acetyltransferase staining of the anterior horn showed that the experimental group and the control group had a significant reduction in the number of immune-positive motor neurons after surgery （23.56±3.18 and 23.08±2.86, respectively） and a gra-dual increase to a stable level at 6 months after surgery, which was slightly lower than that in the control group （23.56±3.18 and 23.08 ±2.86 vs 25.53±3.42, F =2.13, P 〉0.05）. Acetylcholinesterase staining of the nerve fibers near the anastomotic stoma showed that at 6 months after surgery, the experimental group had a significantly higher motor fiber count than the normal group and the control group （45.97±7.76 vs 38.15±5.65 and 37.36±6.10, F =5.92, P 〈0.05）. Conclusion There is a change in the plasticity of C 3-4 segments after C 3-4 nerve root transposition for C 5-6 nerve repair, with regeneration of spinal cord anterior horn motor neurons and myelinated nerve fibers and good recovery of neurological function.