人类大脑或脊髓损伤后,一般都会导致终身残疾,周围神经系统能否再生全凭运气,但在生物界,神经系统能以一种完全不同的方式重新修复。
澳大利亚和美国研究人员联合研究发现,一种线虫具有与传统模式完全不同的神经系统再生机制,新机制对人类神经系统修复具有重要意义。该研究发表在《发育动力学》杂志上。
澳大利亚昆士兰大学脑科学研究院(QBI)和美国纽约艾伯特·爱因斯坦医学院、得克萨斯大学奥斯汀分校共同进行了这项研究,试验对象是一种名为Caenorhabditis elegans(C. elegans)的线虫。这种线虫的神经轴突再生机制与传统模式完全不同,是一种轴突融合的过程。轴突是神经元之间像电缆似的结构,负责传导电流脉冲。QBI马斯莫·希利亚德博士在实验室中利用荧光图像研究轴突融合过程时发现, C. elegans线虫是在损伤的位点架起桥梁,让切断的轴突重新恢复原来的轨道,而传统模式是在远离“出事地点”的地方再生整个“电缆”。
研究小组成员之一、博士后布伦特·诺依曼说:“神经损伤后会以多种不同的方式重新连接。而轴突融合是一种效率很高的方式,能在目标组织之间重建神经连接。这一过程在淡水鳌虾、蚯蚓、水蛭和线虫中都存在。”
由于对C. elegans进行基因分析非常容易,研究人员下一步将集中研究调控该过程的细胞和分子机制,即机体无法正常工作后,这一程序是如何启动的。未来我们或可在人类中发现类似过程,研制出人类神经修复的新方法。(生物谷Bioon.com)
生物谷推荐原文出处:
Developmental Dynamics DOI: 10.1002/dvdy.22606
Axonal regeneration proceeds through specific axonal fusion in transected C. elegans neurons
Brent Neumann1, Ken C. Q. Nguyen2, David H. Hall2, Adela Ben-Yakar3, Massimo A. Hilliard1,*Article first published online: 17 MAR 2011
Keywords:axonal fusion;axonal regeneration;C. elegans;axonal degeneration
Abstract
Functional neuronal recovery following injury arises when severed axons reconnect with their targets. In Caenorhabditis elegans following laser-induced axotomy, the axon still attached to the cell body is able to regrow and reconnect with its separated distal fragment. Here we show that reconnection of separated axon fragments during regeneration of C. elegans mechanosensory neurons occurs through a mechanism of axonal fusion, which prevents Wallerian degeneration of the distal fragment. Through electron microscopy analysis and imaging with the photoconvertible fluorescent protein Kaede, we show that the fusion process re-establishes membrane continuity and repristinates anterograde and retrograde cytoplasmic diffusion. We also provide evidence that axonal fusion occurs with a remarkable level of accuracy, with the proximal re-growing axon recognizing its own separated distal fragment. Thus, efficient axonal regeneration can occur by selective reconnection and fusion of separated axonal fragments beyond an injury site, with restoration of the damaged neuronal tract.