一個受傷的小鼠大腦內(nèi)受損的中樞神經(jīng)系統(tǒng)纖維,，有能力在未受傷區(qū)域以與周圍神經(jīng)系統(tǒng)中的神經(jīng)再生差不多的速度再發(fā)育,。本期Nature Communications上報告的這些發(fā)現(xiàn)與人們通常所持觀點是矛盾的，后者認為：中樞神經(jīng)系統(tǒng)沒有在受傷后再生的能力,。
中樞神經(jīng)系統(tǒng)的受傷導(dǎo)致很多微觀結(jié)構(gòu)變化,，并會造成一系列影響，其中包括癱瘓,、說話不清楚和肌肉無力,。雖然這一研究領(lǐng)域的大部分工作都關(guān)注的是脊髓和中樞神系統(tǒng)的白質(zhì)，但我們對富含神經(jīng)元的灰質(zhì)中所發(fā)生的變化的認識卻是有限的,。Vincenzo De Paola及其同事利用延時顯微鏡來在一年的時間內(nèi)監(jiān)測活小鼠受傷的腦中神經(jīng)回路的反應(yīng),。他們發(fā)現(xiàn)，特定類型的神經(jīng)纖維能自然地再生,，其再生的長度是正常情況下在未受傷的腦中所沒有的,，而造成這一現(xiàn)象的部分原因是，附近沒有分泌抑制性生長因子的“膠質(zhì)瘢痕”,。
雖然作者承認他們并不完全了解哺乳動物腦中軸突再生的機制,，但他們希望這些顯微方法對于通過以前不可能的方式驗證修復(fù)策略將會有用。（生物谷Bioon.com）
生物谷推薦英文摘要：
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.
