微囊化转NGF基因3T3细胞修复大鼠周围神经损伤的实验研究

目的 探讨微囊化转NGF基因3T3细胞移植促进神经再生的可行性。方法 带有小鼠NGF基因的质粒pcDNA3．1 ／NGF经FuGENE^TM6转染NIH 3T3细胞，用APA(海藻酸钠-多聚赖氨酸-海藻酸钠)微胶囊包埋后，进行体外培养，定期检测微囊化细胞活性和NGF分泌量变化。同时，将转基因细胞移植于大鼠坐骨神经切断吻合处，于手术后4、8、12周检测神经再生和功能恢复结果。结果 微囊化转NGF基因3T3细胞在体外培养条件下可存活3个月并能稳定表达，移植于损伤坐骨神经的微囊化转NGF基因细胞组再生神经密度大，排列有序，吻合口瘢痕少，单核细胞浸润少，水肿轻，动作电位幅值和传导速度显著增大，坐骨神经功能指数明显升高。结论 微囊化转NGF基因3T3细胞移植可显著促进神经再生和降低异体细胞移植免疫反应。

An experimental study on repair of peripheral nerve injury by transplantation of microcapsulated NGF-expressing NIH 3T3 cells

Objective To investigate the feasibility of promoting nerve regeneration by using microcapsulated NGF expressing cells transplantation. Methods The plasmid pcDNA3.1+/NGF, containing rat NGF gene, was transfected into the NIH 3T3 cell by using FuGENE TM 6 transfection reagent. The genetically modified cells expressing NGF gene were enclosed within the alginate polylysine alginate(APA) microcapsules and then cultured in vitro .The growth and NGF secretion of the cells were measured periodically. At the same time, these microcapsulated NGF expressing cells were transplanted into the injured sciatic nerve. The regeneration and functional recovery of the nerve were evaluated in 4 weeks, 8 weeks and 12 weeks after the operation. Results The microcapsulated cells had survived and secreted the NGF in three months in vitro. In the group with microcapsulated NGF expressing cells ,the number of the regenerated axons was in large and the nerve fibers were arranged regularly. Compared to other groups, there was less scar ,edema and monocytes found at the stoma in the goup.The moter nerve conductive velocity, nerve muscle action potential and SFI were improved. Conclusions The microcapsulated NGF expressing cells could significantly enhance the nerve regeneration and reduce inflammatory response of xenograft. ;