【摘要】 目的:探讨周围神经放射性损伤产生的过程和机制。方法:利用立体定向放射外科技术照射新西兰大白兔的右下肢坐骨神经,12只兔随机分为2组(n=6),1组单次等中心剂量80 Gy,2组25 Gy。每组再分为2个小组(n=3),分别在照射后5和7个月处死,取受照射和正常的神经段,行电镜观察和S-100免疫组化染色。结果:80 Gy照射后神经纤维坏死严重,S-100蛋白无表达。25 Gy照射后5个月受照神经电镜下表现为脱髓鞘改变;7个月受照神经髓鞘和轴突均出现明显的变性坏死,同时发现神经再生,两组S-100染色均呈强阳性染色。结论:周围神经的放射性损伤起始于射线直接引起髓鞘和轴突的变性坏死,较低剂量照射后,神经发生变性坏死的同时,神经再生已启动;高剂量照射后的神经损伤不可恢复。更多还原

【Abstract】 OBJECTIVE: To investigate the procedure and mechanism of radio-induced peripheral nerve injury in rabbit by stereotactic radiosurgery.METHODS: Twelve rabbits were randomized into two groups(n=6) whose right sciatic nerves were irradiated by stereotactic radiosurgery with single fraction of 25 Gy or 80 Gy,the left sciatic nerve served as a control.Then each group was divided into two groups(n=3),and was euthanized 5 months and 7 months after irradiation respectively.Their ultrastructural and immunohistochemical analyses were performed respectively.RESULTS: The nerve irradiated with 80 Gy showed prominent degeneration and necrosis of axon and myelin,and S-100 protein almost showing no positive expression.Myelinoclasis was observed under the electron microscope 5 months after radiation.Degeneration and necrosis of axon and myelin was found 7 months after radiation,and regeneration existed at the same time.But the S-100 protein showed strong positive expresion.CONCLUSIONS: Radiation can cause degeneration and necrosis of axon and myelin directly.The nerve injury caused by a lower dose is repairable,while by a higher dose is not.更多还原