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,单次等中心剂量25 Gy。兔随机分为三组,分别在照射后3月、5月、7月处死,取受照射和对照的神经段,行电镜、光镜观察和病理图像分析。结果3月时照射神经电镜、光镜或病理图像分析结果与对照神经均无显著差异；5月时受照神经电镜下表现为脱髓鞘改变,病理图像分析结果与对照神经无显著差异；7月时受照神经髓鞘和轴突均出现明显的变性坏死,同时发现神经再生和间质胶原纤维增生。结论周围神经的放射性损伤起始于射线直接引起的髓鞘和轴突的变性坏死,雪旺细胞和损伤后的轴突均有潜在的再生和修复能力。但随后发生的神经间质纤维化会影响神经的再生并使损伤随时间进展。
Objective To investigate the process and mechanism of radiation-induced injury of rabbit peripheral nerve by stereotactic radiosurgery. Methods 12 rabbits were equally randomized into three groups, with their right sciatic nerves of the rabbits irradiated by stereotactic radiosurgery with single fraction of 25 Gy for 3 months, 5 months and 7 months, respectively, and the left sciatic nerves served as controls, followed by performing ultrastructural and morphometric analysis of the bilateral peripheral nerves. Results No prominent changes were observed 3 months after radiation in ultrastructural and morphometric analysis, but 5 months after irradiation, myelinoclasis was seen under the electron microscope in spite of normal axons, even if the differences were no significant via morphometric analysis comparing to the controls. Interestingly, 7 months after the radiation, the ultrastructural analysis showed prominent degeneration and necrosis of axon and myelin, and regeneration and fibrosis began to show up at the same time, and on the other hand, morphometric analyses showed the axon shrank in diameter and myelin sheath in the irradiation groups grew thicker than the controls did. Conclusion Radiation can cause direct degeneration and necrosis of axon and myelin. Schwann cell and injured axon have potential ability to regenerate and repair. Subsequent interstitial fibrosis will impact nerve regeneration and aggravate the damage.
出处
《中华神经医学杂志》
CAS
CSCD
2006年第8期764-766,共3页
Chinese Journal of Neuromedicine
关键词
周围神经
坐骨神经
放射性损伤
放射外科
Peripheral nerve
Sciatic nerve
Radiation-induced injury
Radiosurgery
