有活性的人工神经导管修复大鼠面神经的实验研究

Repair of facial nerve with bioactive artificial nerve conduit:experiment with rats

目的探讨胶原细胞源性神经生长因子(GDNF)基因转染的许旺细胞与聚乳酸/聚羟基乙酸(PLGA)管复合构建的人工神经导管在修复面神经缺损方面的优势。方法利用乳鼠臂丛神经和坐骨神经取材,双酶消化法培养许旺细胞,PcDNA3.1(+)/GDNF 质粒通过脂质体转入许旺细胞。与 PLGA 管构建有生物活性的人工神经导管。将30只 SD 大鼠随机分成3组,分别用直接缝合(A 组),未转染的许旺细胞与 PLGA 管(B 组),转染的许旺细胞与 PLGA 管修复面神经缺损(C 组)。术后2周,1个月,2个月,3个月分别进行大体观察、面神经肌电图、有髓神经纤维计数和髓鞘厚度测量。结果 C 组的面神经肌电图较 A,B 组恢复快,且差异有统计学意义;A,B 组之间神经肌电图差异无统计学意义。C 组的有髓神经纤维计数和髓鞘厚度均较 A,B 组高,差异有统计学意义。结论GDNF 基因转染的许旺细胞复合 PLGA 管构建的具有生物活性的人工神经导管在修复面神经缺损方面优势明显。

Objective To evaluate the effect of bioactive artificial nerve conduits in the repair of facial nerve defects. Methods Schwann cells （SC） were collected from the sciatic nerve and brachial plexus of a newborn SD rat, cultured, transfected with the plasmid pcDNA3.1 （ ＋ ）/GDNF containing glial cell line-derived neurotrophic factor gene, digested by pancreatin to make mixture of cell suspension to be injected into poly （L-lactic-co-glycolic acid） conduits. Mter injected with SCs, the conduits were cultured in for 2 weeks. Thirty female SD rat underwent buccal branch of facial nerve and then were randomly divided into 3 groups ： Group A, undergoing direct anastomosis of the amputated dextral nerve; Group B, in which the 2 sides of amputated nerve were put into the PLGA conduit without transfected GDNF; and Group C in which the 2 sides of amputated nerve were put into the PLGA conduit with transfected GDNF. The motion of the facial muscles and whisker was observed. Two weeks, and 1, 2, and 3 months after the operation electrophysiological study was conducted to measure the action potential of the facial nerve. Then the rata were killed with their bilateral facial nerve and pontes were taken out to undergo histological examination. Results Compound action potential could be detected in all groups at any time points except in Groups A and B 2 weeks after the operation. The values of compound action potential of Group C at different time points were all significantly higher than those of Groups A and B （ all P 〈 0.01 ）. However, there were not significant differences in the compound action potential values at any time point between Groups A and B （ all P 〉 0.05）. The mean number of myelinated nerve fibers, thickness of myelin sheath, and number of motor neuron of Group C were all significantly higher than those of Groups A and B （ all P 〈 0.05 ）. Conclusion Conduit with SCs transfected with GDNF gene ＋ PLGA is superior to that with SCs ＋ PLGA and direct anastomosis in repair of facial nerve.