GDNF基因修饰的雪旺细胞对大鼠坐骨神经缺损的修复作用

Effects of GDNF-modified Schwann cells on repair of sciatic nerve defect in rats

目的 应用携带胶质细胞源性神经营养因子基因的逆转录病毒载体质粒 (pLXSN GDNF)对体外培养的雪旺细胞进行基因修饰 ,并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)管构建神经移植复合体 ,用于大鼠坐骨神经缺损的修复 ,同时对其促轴突再生及神经元保护作用予以检测评价。方法 40只成年Wistar大鼠随机分为4组 :A组 (n =10 )细胞外基质凝胶 PLGA管桥接组 ;B组 (n =10 )雪旺细胞 细胞外基质凝胶 PLGA管桥接组 ;C组 (n =10 )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 =10 )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 ,辣根过氧化物酶神经逆行示踪技术用于脊髓前角运动神经元再生评价。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、透射电镜超微结构观察以及脊髓前角运动神经元再生评价结果提示 :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 Schwann cells on the repair of sciatic nerve defects in rats. Methods Forty adult Wistar rats were randomly divided into four groups: group A (nerve grafts, fabricated by extracellular gel and PLGA conduits, n=10), group B (Schwann cells and extracellular gel and PLGA conduits, n=10), group C (GDNF-modified Schwann cells and extracellular gel and PLGA conduits, n=10), and group D (autograft, n=10). Motoneuron conduction and morphology (including anatomical measures and ultrastructure) of the regenerated axons were investigated at 12 weeks postoperatively. Regeneration rate of the motoneuron in spinal cord was also evaluated by using HRP label technique. Results Higher rate of nerve regeneration or number of labeled motoneurons in spinal cord was observed using PLGA conduits seeded with GDNF enhanced expressing Schwann cells (group C) than that with PLGA conduits (group A) alone or PLGA conduits seeded with control Schwann cells (group B), but there was no significant difference as compared with that in the autograft group (group D). Conclusion These results suggest that using gene transfer techniques to increase neurotrophic factor expression in Schwann cells added to nerve grafts may be a promising method for improving nerve regeneration.