Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal.
PLoS One. 2012;7(6):e38647. doi: 10.1371/journal.pone.0038647. Epub 2012 Jun 20.
The emerging model for the adult subependymal zone (SEZ) cell population indicates that neuronal diversity is not generated from a uniform pool of stem cells but rather from diverse and spatially confined stem cell populations. Hence, when analysing SEZ proliferation, the topography along the anterior-posterior and dorsal-ventral axes must be taken into account. However, to date, no studies have assessed SEZ proliferation according to topographical specificities and, additionally, SEZ studies in animal models of neurological/psychiatric disorders often fail to clearly specify the SEZ coordinates. This may render difficult the comparison between studies and yield contradictory results. More so, by focusing in a single spatial dimension of the SEZ, relevant findings might pass unnoticed. In this study we characterized the neural stem cell/progenitor population and its proliferation rates throughout the rat SEZ anterior-posterior and dorsal-ventral axes. We found that SEZ proliferation decreases along the anterior-posterior axis and that proliferative rates vary considerably according to the position in the dorsal-ventral axis. These were associated with relevant gradients in the neuroblasts and in the neural stem cell populations throughout the dorsal-ventral axis. In addition, we observed spatially dependent differences in BrdU/Ki67 ratios that suggest a high variability in the proliferation rate and cell cycle length throughout the SEZ; in accordance, estimation of the cell cycle length of the neuroblasts revealed shorter cell cycles at the dorsolateral SEZ. These findings highlight the need to establish standardized procedures of SEZ analysis. Herein we propose an anatomical division of the SEZ that should be considered in future studies addressing proliferation in this neural stem cell niche.
成人室管膜下区（SEZ）细胞群体的新兴模型表明，神经元的多样性不是由一个统一的干细胞池产生的，而是由不同的、空间受限的干细胞群体产生的。因此，在分析 SEZ 增殖时，必须考虑到沿前后和背腹轴的地形。然而，迄今为止，尚无研究根据地形特异性评估 SEZ 增殖，此外，神经/精神疾病动物模型中的 SEZ 研究通常未能明确指定 SEZ 坐标。这可能会使研究之间的比较变得困难，并产生矛盾的结果。更重要的是，通过关注 SEZ 的单一空间维度，相关的发现可能会被忽视。在这项研究中，我们描述了整个大鼠 SEZ 前后和背腹轴的神经干细胞/祖细胞群体及其增殖率。我们发现 SEZ 增殖沿着前后轴减少，并且增殖率根据背腹轴的位置而有很大差异。这与背腹轴上整个神经母细胞和神经干细胞群体的相关梯度相关。此外，我们观察到 BrdU/Ki67 比值的空间依赖性差异，这表明 SEZ 中增殖率和细胞周期长度存在很大的可变性；因此，对神经母细胞的细胞周期长度的估计显示，在背外侧 SEZ 中细胞周期较短。这些发现强调了需要建立 SEZ 分析的标准化程序。在此，我们提出了 SEZ 的解剖学划分，在未来研究这个神经干细胞龛中的增殖时应考虑该划分。
