电针对脊髓损伤后少突胶质细胞再髓鞘化的影响

Effect of electroacupuncture on proliferation of oligodendrocytes and remyelination of axons after spinal cord injury

目的:观察电针治疗对脊髓损伤后少突胶质细胞增生及新生轴突髓鞘再形成的影响。方法:选用成年大鼠,制作中度脊髓损伤模型,应用督脉电针治疗。电镜观察各组髓鞘和少突胶质细胞的超微结构变化;原位杂交显示髓磷脂碱性蛋白(myelin basic protein,MBP)的基因表达。结果:脊髓损伤后髓鞘明显肿胀,部分崩解;少突胶质细胞坏死溶解。1-2周后出现少量增生少突胶质细胞和厚薄不等的髓鞘。电针组髓鞘肿胀较轻,少突胶质细胞坏死少。1周后可见较多增生的少突胶质细胞和完整髓鞘。原位杂交显示电针组MBP基因表达明显高于损伤组,3 d组最低,1周达高峰,此后逐渐下降。结论:脊髓损伤后电针治疗可有效防止神经纤维的溃变,促进少突胶质细胞增生和再生神经纤维髓鞘再形成。

To investigate the effect of electroacupuncture on the proliferation of oligodendrocytes and remyelination of regenerated nerve fibers after spinal cord injury. Methods： Female adult Wistar rats were used to make medium-degree spinal cord injury model by Allen＇s method. The rats were treated with electroacupuncture on DU Channel （group EA） for 3 days, 1 week, 2 weeks, or 4 weeks; the control group were given methylprednisolone （group MP） or nothing （group C）. The ultrastructure of myelin sheath and oligodendrocytes were observed by electron microscope. The expression of myelin basic protein （MBP） was examined by in situ hybridization. Results： In group C, the myelin sheaths were seriously swollen, and part of them were disrupted. Some oligodendrocytes were necrotic and resolved. 1-2 weeks after injury d few proliferated oligodendrocytes and remyelinisated axons were detected. In group EA and group MP, less myelin sheaths were swollen, and less oligodendrocytes were necrotic. There were many axons remyelinisated and oligodendrocytes proliferated. The expression of MBP mRNA in group EA and MP was enhanced much more than that in group C. The positive oligodendroctyes were the least in the 3^rd day group than that in all the other groups; it reached the maximum after 1 week and then decreased gradually. Conclusion： Treatment with electroacupuncture after spinal cord injury may inhibit degeneration of nervous fibers, and promote proliferation of oligodendrocytes and remyelination of regenerated and demyelinated axons.