去细胞异种神经复合神经生长因子修复神经缺损的实验研究

目的 应用含有神经生长因子(NGF)的去细胞异种神经基膜管作为神经移植替代物桥接大鼠坐骨神经缺损,观察其对神经再生的作用.方法 选用Wistar大鼠45只,随机分为3组,每组15只,于术制成右后肢坐骨神经长10 mm的神经缺损,取兔胫神经制成去细胞神经基膜管,电镜及HE染色观察神经基膜管超微结构,流式细胞仪检测去细胞前后神经主要组织相容性抗原Ⅱ(MHC Ⅱ)的变化情况.A组以含有NGF的去细胞异种神经基膜管桥接神经缺损,B组单纯采用去细胞异种神经基膜管桥接神经缺损,C组采用自体神经移植修复神经缺损.术后1个月行神经电生理检测即胫后肌群运动诱发电位,用HE染色、免疫组化染色、透射电镜等方法对移植体远端吻个口再生神经纤维进行形态学观察,并对再生有髓神经纤维的数量、密度、直径及雪旺细胞的密度进行量化分析.结果 移植前新鲜神经组MHC-Ⅱ检测值为72.14±19.88,去细胞组MHC-Ⅱ检测值为4.19±3.11,两组比较差异有统计学意义(t=3.817,P＜0.05);透射电镜观察显示为胶原性管道,无细胞成分.术后4周,处死前行运动诱发电位检测,神经传导速度A组为(21.16±2.31)m/s,B组为(13.37±1.89)m/s,C组为(21.43±2.18)m/s,A组与 C组比较差异无统计学意义(P＞0.05),A组与 B组比较差异有统计学意义(P＜0.05).组织学观察见3组移植体远端吻合口横切面再生神经纤维呈微束状,透射电镜观察再生神经纤维具有正常的形态和结构.A、C组再生神纤纤维数量及直径均优于B组,差异有统计学意义(P＜0.05).结论 经化学萃取的去细胞兔胫神经基膜管能够移植于大鼠,成功修复大鼠坐骨神经缺损,而且复合NGF的去细胞基膜管在神经修复质量上优于单纯的去细胞神经基膜管,更加接近自体神经移植的效果.

Repair of peripheral nerve gap with xenogeneic acellular graft combined with nerve growth factor

Objective To evaluate peripheral nerve regeneration in the adult Wistar rats whose nerve gaps were repaired by acellular basal lamina tubes combined with nerve growth factor (NGF).Methods Fifteen adult Wistar rats were divided randomly into 3 even groups. A 1.0 cm long gap was created in the continuity of the sciatic nerve in each rat. The rabbit tibial nerve was excised to make xenogeneic acellular nerve basal lamina tubes, the ultrastructure of which was observed by electron microscopy and HE coloration. The MHC Ⅱ antigen contents were examined by flow cytometry before and after the rabbit tibial nerves were treated with chemical detergents. In group A, xenogeneic acellular basal lamina tubes were grafted with NGF; in group B, only xenogeneic acellular basal lamina tubes were grafted; in group C, autogenous nerves were grafted. The nerve functional restoration was observed by electrophysiological experiments in all rats one month postoperatively in terms of motor evoked potential of the musculus triceps surae and the motor conduction velocity at the grafted sciatic nerve segments. Morphological and morphometric analyses were done by optical microscopy, electron microscopy and immunohistochemical techniques. Results The nerve regeneration, nerve fiber arrangement and nerve function reconstruction in group A were better than in group B, and similar to those in group C. Conclusions The rabbit tibial nerve treated with chemical detergents can be grafted to repair the nerve gap in rats. As the acellular basal lamina tubes combined with NGF can better improve nerve regeneration by enhancing the growth of regenerating axons and migration of Schwann cells than those without NGF, they may be a good substitute for nerve grafts.