成年斑马鱼视神经再生期间顶盖表面纤维层和灰质层的突触形态学研究(英文)

SYNAPTOLOGICAL STUDY ON SUPERFICIAL FIBER AND GRAY STRATUM IN THE TECTUM DURING THE OPTIC REGENERATION IN ADULT ZEBRAFISH

目的 研究斑马鱼视神经再生过程中神经递质的变化,探讨神经递质和神经再生的关系。 方法 应用斑马鱼视神经再生模型,通过电镜技术观察顶盖表面纤维和灰质层突触的形态变化。 结果 视神经损伤后 顶盖突触变化过程大致可分4个时期:1.视神经损伤后早期顶盖突触结构的退变;突触密度和突触小泡密度均下 降,空型终末密度增大,8d时突触小泡密度降到最低水平;而空型终末密度最高。2.损伤后14d再生纤维大量进 入顶盖;这一时期大核小泡和小核小泡密度都大量增加,但进入顶盖的纤维还没有或很少形成突触,14d时突触密 度降到最低。3.损伤后21d的特征是突触大量形成和圆形清亮小泡、扁平清亮小泡密度增加。4.再生晚期突触 形态和功能恢复及精确化;100d时突触密度和突触小泡密度都大体恢复正常,但大核小泡密度还很高。 结论 兴奋性神经递质和抑制性神经递质可能对早期神经再生的启动和突触的形成起重要作用,而肽类和胺类可能对再 生轴突的投射和精确化有重要作用;神经递质促进神经再生有先后顺序。

Objective To investigate the changes of neurotransmitters and the relationship between neurotransmitters and nerve regeneration during the optic regeneration in zebrafish.Methods Using the classical retinotectal regeneration model and electromicroscopy,we observed the ultrastructural changes of synapses of the superficial fiber and gray stratum(SFGS)in the tectum. Results The morphological changes of synapses can be divided into 4 stages:1.Synaptic degeneration at the early stage after lesion.2. Regenerating optic nerve fibers entered the SFGS laminar of the tectum,the densities of large granule vesicles(LGV)and small granule vesicles(SGV)were increased.3. Lots of synapses were formed,the densities of small round clear vesicles(SCV)and small flat clear vesicles(FCV)were increased dramatically.4. Morphological recovery and refinement of the retinotopic innervation.Conclusion Neurotransmitters might play an important role during the regeneration of optic nerve,and they exhibited their effects in a chronological way.