Jiang Bo, Zhang Yong, Zhao Jiaju, She Chang, Zhou Xiaozhong, Dong Qirong, Wang Peiji
a Department of Hand and Foot Surgery, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, P. R. China.
b Department of Orthopedics, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, P. R. China.
Radiat Res. 2017 Oct;188(4):455-462. doi: 10.1667/RR14799.1. Epub 2017 Aug 10.
Low-dose radiation has been used in clinical and experimental models for the prevention of scarring and for fracture healing. There is evidence that low-dose radiation improves the hormesis of various cell types but little is known about its effects on peripheral nerve tissue. In this study, we investigated the beneficial effects of low-dose radiation on the regeneration of transectional peripheral nerve injury in an experimental rat model. Seventy-two male Sprague-Dawley rats received transection injury to the left sciatic nerves, and the nerves were subsequently sutured by epineurium end-to-end anastomosis to restore continuity. Animals were randomly assigned to one of two treatment groups (n = 36/group): 1 Gy X-ray irradiation or control (sham irradiation). Gait analysis, electrophysiological examination and morphological investigations were performed. In addition, Western blot and qRT-PCR were performed to determine the level of vascular endothelial growth factor (VEGF) and growth-associated protein-43 (GAP-43). Content of VEGF and GAP-43 in the regenerated sciatic nerve of the irradiated group was higher than the control group. At 4 to 12 weeks after surgery, the irradiated animals exhibited a significantly improved functional recovery relative to controls. At 12 weeks after surgery, amplitude and conduction velocity of the irradiated group were higher than the control group (P < 0.05). The number of nerve fibers, diameter of axons and morphological structure of the myelin sheath in the irradiated group were superior to those of the control group. These results suggest that low-dose radiation contributed to regeneration and functional recovery after transverse peripheral nerve injury by inducing increased production of VEGF and GAP-43, which promote the axonal regeneration and myelination.
低剂量辐射已被应用于临床和实验模型中，用于预防瘢痕形成和促进骨折愈合。有证据表明，低剂量辐射可改善各种细胞类型的兴奋效应，但对其对外周神经组织的影响知之甚少。在本研究中，我们在实验大鼠模型中研究了低剂量辐射对横断性外周神经损伤再生的有益作用。72只雄性Sprague-Dawley大鼠接受左侧坐骨神经横断损伤，随后通过神经外膜端端吻合术缝合神经以恢复连续性。动物被随机分配到两个治疗组之一（每组n = 36）：1 Gy X射线照射或对照组（假照射）。进行了步态分析、电生理检查和形态学研究。此外，还进行了蛋白质免疫印迹和定量逆转录聚合酶链反应，以确定血管内皮生长因子（VEGF）和生长相关蛋白43（GAP-43）的水平。照射组再生坐骨神经中VEGF和GAP-43的含量高于对照组。术后4至12周，与对照组相比，照射动物的功能恢复明显改善。术后12周，照射组的波幅和传导速度高于对照组（P < 0.05）。照射组的神经纤维数量、轴突直径和髓鞘的形态结构均优于对照组。这些结果表明，低剂量辐射通过诱导VEGF和GAP-43的产生增加，促进轴突再生和髓鞘形成，从而有助于外周神经横断损伤后的再生和功能恢复。
