一个受伤的小鼠大脑内受损的中枢神经系统纤维，有能力在未受伤区域以与周围神经系统中的神经再生差不多的速度再发育。本期Nature Communications上报告的这些发现与人们通常所持观点是矛盾的，后者认为：中枢神经系统没有在受伤后再生的能力。
中枢神经系统的受伤导致很多微观结构变化，并会造成一系列影响，其中包括瘫痪、说话不清楚和肌肉无力。虽然这一研究领域的大部分工作都关注的是脊髓和中枢神系统的白质，但我们对富含神经元的灰质中所发生的变化的认识却是有限的。Vincenzo De Paola及其同事利用延时显微镜来在一年的时间内监测活小鼠受伤的脑中神经回路的反应。他们发现，特定类型的神经纤维能自然地再生，其再生的长度是正常情况下在未受伤的脑中所没有的，而造成这一现象的部分原因是，附近没有分泌抑制性生长因子的“胶质瘢痕”。
虽然作者承认他们并不完全了解哺乳动物脑中轴突再生的机制，但他们希望这些显微方法对于通过以前不可能的方式验证修复策略将会有用。（生物谷Bioon.com）
生物谷推荐英文摘要：
Nature Communications DOI:10.1038/ncomms3038
In-vivo single neuron axotomy triggers axon regeneration to restore synaptic density in specific cortical circuits
A. J. Canty, L. Huang, J. S. Jackson, G. E. Little, G. Knott, B. Maco & V. De Paola
To what extent, how and when axons respond to injury in the highly interconnected grey matter is poorly understood. Here we use two-photon imaging and focused ion beam–scanning electron microscopy to explore, at synaptic resolution, the regrowth capacity of several neuronal populations in the intact brain. Time-lapse analysis of >100 individually ablated axons for periods of up to a year reveals a surprising inability to regenerate even in a glial scar-free environment. However, depending on cell type some axons spontaneously extend for distances unseen in the unlesioned adult cortex and at maximum speeds comparable to peripheral nerve regeneration. Regrowth follows a distinct pattern from developmental axon growth. Remarkably, although never reconnecting to the original targets, axons consistently form new boutons at comparable prelesion synaptic densities, implying the existence of intrinsic homeostatic programmes, which regulate synaptic numbers on regenerating axons. Our results may help guide future clinical investigations to promote functional axon regeneration.
