神经干细胞移植对大鼠损伤视神经超微结构的实验研究

Effect of transplantation of neural stem cells on uitrastructure of injured rat optic nerve

目的探讨神经干细胞（NSCs）移植治疗视神经损伤的新方法，为治疗视神经损伤打下基础。方法制作视神经损伤大鼠模型，分别在急性损伤期和损伤后4周一次性向视神经受损区鞘膜内注射NSCs。注射后4周断颈处死动物，在电镜下观察损伤视神经超微结构。结果损伤后视神经轴突减少，伴有水泡样变性，髓鞘厚薄不一，结构疏松，局部有缺损破碎，出现脱髓鞘现象，基质增多。NSCs移植组轴突数目增多，水泡样变性少见，髓鞘修复基本完整：延期移植组更加明显；对照组轴突变得透明空虚，髓鞘变成薄膜样结构，可见到鞘膜泡状分离和碎屑．基质成分明显增多。结论NSCs移植可使损伤视神经超微结构得到有效修复，其有望成为治疗视神经损伤的有效手段。

Objective To detect the ultrastructural changes of injured optic nerve after transplanted with neural stem cells （NSCs） derived from the embryonic rat brains in a rat model of the crushed optic nerve. Methods The optic nerve injury models were induced in rats by forceps-holder way. NSCs were transplanted into the crushed optic nerve immediately after injury or 4 weeks later, and the animals were killed 4 weeks after injection. The ultrastructural changes of injured optic nerve were observed under electron microscope. Results The axon number of crushed optic nerve was decreased with bubble-like degeneration, and the structure of myelin was loose and uneven in thickness, even broken somewhere, and demyelination and increased matrix were found in the injured optic nerve. Four weeks after NSCs transplantation, the axon number was increased and axonal degeneration was ameliorated, and the structure of myelin was almost recovered, especially more effectively in the delayed transplantation group. In contrast, the control group displayed the degraded axon, the denatured and disintegrated myelin and the increased matrix. Conclusion NSCs transplantation can restore the ultrastructure of the injured optic nerve and be an effective way to cure optic nerve injury.