Luzzati Federico, De Marchis Silvia, Fasolo Aldo, Peretto Paolo
Department of Animal and Human Biology, University of Turin, 10123 Turin, Italy.
J Neurosci. 2006 Jan 11;26(2):609-21. doi: 10.1523/JNEUROSCI.4371-05.2006.
Stem cells with the potential to give rise to new neurons reside in different regions of the adult rodents CNS, but in vivo only the hippocampal dentate gyrus and the subventricular zone-olfactory bulb system are neurogenic under physiological condition. Comparative analyses have shown that vast species differences exist in the way the mammalian brain is organized and in its neurogenic capacity. Accordingly, we have demonstrated recently that, in the adult rabbit brain, striking structural plasticity persists in several cortical and subcortical areas. Here, by using markers for immature and mature neuronal and glial cell types, endogenous and exogenously administered cell-proliferation markers, intraventricular cell tracer injections coupled to confocal analysis, three-dimensional reconstructions, and in vitro tissue cultures, we demonstrate the existence of newly formed neurons in the caudate nucleus of normal, untreated, adult rabbit. Our results suggest that neurogenesis in the caudate nucleus is a phenomenon independent from that occurring in the adjacent subventricular zone, mostly attributable to the activity of clusters of proliferating cells located within the parenchyma of this nucleus. These clusters originate chains of neuroblasts that ultimately differentiate into mature neurons, which represent only a small percentage of the total neuronal precursors. These results indicate that striatum of rabbit represents a favorable environment for genesis rather than survival of newly formed neurons.
具有产生新神经元潜力的干细胞存在于成年啮齿动物中枢神经系统的不同区域，但在生理条件下，只有海马齿状回和脑室下区 - 嗅球系统在体内具有神经发生能力。比较分析表明，哺乳动物大脑的组织方式及其神经发生能力存在巨大的物种差异。因此，我们最近证明，在成年兔脑中，几个皮质和皮质下区域存在显著的结构可塑性。在这里，我们通过使用未成熟和成熟神经元及胶质细胞类型的标志物、内源性和外源性细胞增殖标志物、脑室注射细胞示踪剂并结合共聚焦分析、三维重建以及体外组织培养，证明了在正常、未经处理的成年兔尾状核中存在新形成的神经元。我们的结果表明，尾状核中的神经发生是一种独立于相邻脑室下区发生的现象，主要归因于位于该核实质内的增殖细胞簇的活动。这些细胞簇产生神经母细胞链，最终分化为成熟神经元，而成熟神经元仅占总神经元前体的一小部分。这些结果表明，兔的纹状体是新形成神经元发生而非存活的有利环境。
