Spontaneous Regeneration of the Serotonergic Descending Innervation in the Sea Lamprey after Spinal Cord Injury
Spontaneous Regeneration of the Serotonergic Descending Innervation in the Sea Lamprey after Spinal Cord Injury
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DOI：
10.1089/neu.2011.1766
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发表时间：
2011-12-01
影响因子：
4.2
通讯作者：
Celina Rodicio, Maria
中科院分区：
文献类型：
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作者：
Eugenia Cornide-Petronio, Maria;Soledad Ruiz, Maria;Celina Rodicio, Maria
与哺乳动物相比，七鳃鳗在脊髓完全横断后能够恢复明显的正常运动，并且脊髓轴突有选择地沿着正确的路径再生。脊髓5-羟色胺能下行投射在哺乳动物和七鳃鳗脊髓水平的运动调节中发挥作用。在这项研究中，我们使用免疫荧光和追踪技术相结合的方法显示，在海鳗中，迷走神经核尾部的5-羟色胺能下行神经元在脊髓完全横断后穿过损伤部位再生轴突。成年海鳗幼体在第5鳃水平横断脊髓，恢复期5个月后，在损伤部位尾侧1 mm处再次显露脊髓，并应用示踪剂神经生物素(TM)。在5-羟色胺免疫反应阳性的迷走神经核尾部，观察到双标记细胞。为了研究神经再支配是由于损伤部位上方的轴突发芽还是由于轴突再生，再次进行了实验，但在横断时应用了示踪剂Fluoro-Gold(TM)。在迷走神经核内观察到三标记细胞，表明至少部分神经再生与真正的再生相对应。这项研究为研究脊椎动物5-羟色胺能下行轴突再生的内在分子机制提供了一个新的有趣的模型。该模型的应用可能为脊髓损伤患者提出新的治疗方法提供有价值的信息。
In contrast to mammals, lampreys are capable of recovering apparently normal locomotion after complete spinal cord transection, and the spinal axons regenerate selectively in their correct paths. Descending serotonergic projections to the spinal cord play a role in the modulation of locomotion at spinal levels in both mammals and lampreys. In this study, we used combined immunofluorescence and tract-tracing techniques to show that in the sea lamprey, serotonergic descending neurons of the caudal rhombencephalon (vagal nucleus) regenerate their axons across the lesion site after complete spinal cord transection. The spinal cord of mature larval sea lampreys was transected at the level of the fifth gill, then after a recovery period of 5 months, the spinal cord was exposed again, 1 mm caudal to the injury site, and the tracer Neurobiotin (TM) was applied. Double-labeled cells were observed in the caudal portion of the serotonin-immunoreactive vagal nucleus of the caudal rhombencephalon. In order to investigate whether the reinnervation was due to sprouting from axons above the injury site or to regeneration of axotomized axons, the experiments were performed again, but the tracer Fluoro-Gold (TM) was applied at the time of transection. Triple-labeled cells were observed in the vagal nucleus, indicating that at least part of the reinnervation corresponds to true regeneration. This study provides a new and interesting model for investigating the intrinsic molecular mechanisms involved in regeneration of the serotonergic descending axons in vertebrates. Use of this model may provide valuable information for proposing new therapies for patients with spinal cord injury.