GDNF基因修饰的人工神经复合体对大鼠坐骨神经缺损的修复作用研究

Mechanisms and effects of GDNF-modified artificial nerve on sciatic nerve defects in rats

目的:应用体外获取的胶质细胞源性神经营养因子(GDNF)基因修饰的雪旺细胞结合细胞外基质凝胶及生物可降解聚乳酸-聚羟基乙酸共聚物(PLGA)管构建的GDNF基因修饰的人工神经复合体修复大鼠坐骨神经缺损,并对其促神经再生作用予以检测评价。方法:20只成年Wistar大鼠随机分为4组,A组(n=5)细胞外基质凝胶-PLGA管桥接组;B组(n=5)雪旺细胞-细胞外基质凝胶-PLGA管桥接组;C组(n=5)GDNF基因修饰的雪旺细胞-细胞外基质凝胶-PLGA管桥接组;D组(n=5)自体神经桥接组。损伤各组12周时应用神经电生理及甲苯胺蓝染色和透射电镜观测神经再生情况。结果:12周时再生神经运动传导速度检测、甲苯胺蓝染色轴突形态计量学分析及透射电镜超微结构观察结果提示C组优于A、B组,而与D组相比无明显差异。结论:雪旺细胞的转基因处理可能弥补单纯细胞移植神经营养因子含量的不足,而可能达到与自体神经移植相似的效果。

Objective:To investigate the effects of GDNF-modified artificial nerve,which fabricated by GDNF-modified Schwann′s cell and extracellular gel and biodegradable PLGA conduits,on sciatic nerve defects in rats.Method:Twenty adult Wistar rats were divided into four groups randomly, Artificial nerve complex, which fabricated by extracellular gel and PLGA conduits(group A,n=5), Schwann′s cells and extracellular gel and PLGA conduits (group B,n=5)or GDNF-modified Schwann cells and extracellular gel and PLGA conduits(group C,n=5) respectively, were used to repair sciatic nerve defects in rats.Group D(n=5) was autograft. Motoneuron conduction and morphology(including anatomical measures and ultrastructure) of regenerated axons were investigated at 12 week postoperatively. Result: Higher rate of nerve regeneration was observed using PLGA conduits seeded with GDNF enhanced expressing Schwann′s cell (group C) than with PLGA conduits (group A)alone or PLGA conduits seeded with control Schwann′s cell(group B),but there was no significant difference when compared with the group of autograft (group D).Conclusion:Using gene transfer techniques to increase neurotrophic factor expression in Schwann′s cell added to artificial nerve grafts may be a promising methods for improving nerve regeneration.Author′s address Research Institute of Field Surgery, Daping Hospital, Third Military Medical University Chongqing,400042