线照射对受损脊髓轴索和髓鞘的作用

　　摘　要：目的，探讨X线对受损脊髓髓鞘和轴索作用。方法：实验组行脊髓胸腰段半横断，术后次日行X线照射，剂量是35Gy。对照组行同样手术，但不照射。24周时行SP(streptavidinperoxidaseconjugataedmethod，链霉素抗生素蛋白-过氧化酶连接法)免疫组化染色和超微结构观察。结果：实验组脊髓损伤平面上、下段MBP(myelinbasicprotein，髓磷脂基蛋白)阳性髓鞘数量明显低于对照组；实验组损伤平面上段NF(neuronfilament，神经纤维丝)阳性神经纤维数量与对照组无明显差别，实验组损伤平面下段NF阳性神经纤维数量高于对照组。电镜下实验组脊髓出现明显脱髓鞘改变，损伤平面下段可见新生的细小神经纤维束。结论：35Gy的X线照射可以使脊髓出现较多的脱髓鞘变化，有促进损伤平面下段NF阳性纤维增多的作用。

The Effect on Myelin Sheath and Axon in the Lesioned rat Spinal Cord by X-irradiation

bai Xizhuang,He Weiwei,Niu Ping(Department of Orthopaedic Surgery, The First Clinical College of China Medical University, Shenyang, 110001)

　　Abstract：Objective: To investigate the effect of x-irridiation on the myelin and axon of the spinal cord. Method: 60 adult rats were divided into two groups-the experimental group and the contrast group. In the former, 30 adult rats with a spinal cord hemisection operation in thoracic lumbar segment received x-irridiation on the second day postoperation and the dosage was 35 Gy. The latter received the same operation and no x-irridiation. 24 weeeks of operation later. We had the SP immunohistochemistry research and supramicrostructure oberservation under transmission electron. Result: The number of MBP positive myelin was less obviously in experimental group than that in the contrast group both in upper section and lower section of spinal cord injury level. The number of NF positive nerve fiber in experimental group was more than that of contrast group in upper section of injury level and no significant difference was observed in lower section. Under transmission electron microscope there was obvious demyelination changes of spinal cord in experimental group and fine newborn nerve fiber bundle could be seen in lower section of injury level. Conclusion: More demylination changes in spinal cord will occur by x-irridiation with 35 Gy dosage and the x-iddidiation will promote the increase of NF positive nerve fiber in lower segment of injury level.

　　Keywords：x-irradiation; spinal cord; myelin sheath; axon参考文献：

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