不同神经移植体移植修复自体周围神经缺损时的再生效果比较

摘要

目的 比较不同自体神经移植材料在移植修复周围混合神经缺损时的再生效果.方法 取45只SD大鼠,随机分成3组,分别切除0.5 cm右侧坐骨神经,建立神经缺损模型.运动神经移植组:取左侧后肢的股神经运动支移植修复缺损的坐骨神经;感觉神经移植组:取左侧后肢的腓肠神经移植修复缺损的坐骨神经;混合神经移植组:取左侧后肢的坐骨神经移植修复.分别于术后2、4和8周,采用神经夹捏实验测量神经再生长度,处死动物后取下术侧腓肠肌称取肌肉湿重.术后8周取胫神经远侧吻合口远端3 mm神经组织行甲苯胺蓝染色,同时电镜下观察神经纤维的直径及髓鞘的厚度,采用图像分析软件进行图片分析,计数神经纤维总数并计算神经纤维的密度.结果 神经再生长度,术后2周时3组间差异无统计学意义;术后4、8周时运动神经移植组及混合神经移植组大于感觉神经移植组(均P<0.05).腓肠肌湿重,术后2、4周时3组间差异无统计学意义;术后8周时运动神经移植组和混合神经移植组重于感觉神经移植组(均P<0.05).术后8周时,在运动神经移植组和混合神经移植组中可见大量神经纤维生长,神经纤维的数量、轴突的密度均大于感觉神经移植组(均P<0.05);再生神经轴突在运动神经移植组更加成熟.结论 不同的神经移植材料对自体神经移植再生效果有着显著影响.运动神经及混合神经移植修复自体周围神经缺损时的再生效果优于感觉神经移植.%Objective To compare effects of different autologous nerve grafts on the regeneration of the peripheral mixed nerve. Methods Nerve defect models were established by removing 0. 5 cm right sciatic nerve in SD rats (n= 45 ). Then ,the animals received motor ,sensory or mixed nerve grafts ,which originated from the femoral nerve ,sural nerve and sciatic nerve of the contralateral hind limb. At 2 ,4 and 8 weeks post operation ,the nerve pinch test was performed to measure the length of the regenerated nerve ,and the wet weight of the gastrocnemius muscle of the operated limb was measured. The tissues (3 mm in length) of the tibial nerve distal to the anastomosis were stained by toluidine blue staining ,and the diameter of the nerve fibers and the thickness of the myelin were determined by electron microscopy on week 8 after operation. Image analysis software was used to analyze the pictures ,and the total number of nerve fibers was counted and the density of nerve fibers calculated. Results Histomorphometry of the regenerated nerves at 8 weeks demonstrated robust nerve regeneration in both motor and mixed nerve graft groups. In contrast ,poor nerve regeneration was observed in sensory nerve graft group ,as evidenced by significantly decreased nerve fiber counts and nerve density when compared with mixed and motor groups (P<0. 05 ). Moreover ,the length of the regenerated nerve in the motor and the mixed nerve graft groups were greater than that in the sensory nerve graft group at 4 and 8 weeks post operation (P<0. 05 ). The wet weight of the gastrocnemius muscle in the motor and the mixed nerve graft groups were greater than that in the sensory nerve graft group at 8 weeks post operation (P<0. 05 ). Conclusion Motor or mixed nerve grafts ,rather than sensory nerve grafts ,contribute to the regeneration of the peripheral mixed nerve.