Institute of Anatomy, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
Eur J Neurosci. 2011 Sep;34(6):978-87. doi: 10.1111/j.1460-9568.2011.07804.x.
Adult hippocampal neurogenesis is a prominent event in rodents. In species with longer life expectancies, newly born cells in the adult dentate gyrus of the hippocampal formation are less abundant or can be completely absent. Several lines of evidence indicate that the regulatory mechanisms of adult neurogenesis differ between short- and long-lived mammals. After a critical appraisal of the factors and problems associated with comparing different species, we provide a quantitative comparison derived from seven laboratory strains of mice (BALB, C57BL/6, CD1, outbred) and rats (F344, Sprague-Dawley, Wistar), six other rodent species of which four are wild-derived (wood mouse, vole, spiny mouse and guinea pig), three non-human primate species (marmoset and two macaque species) and one carnivore (red fox). Normalizing the number of proliferating cells to total granule cell number, we observe an overall exponential decline in proliferation that is chronologically equal between species and orders and independent of early developmental processes and life span. Long- and short-lived mammals differ with regard to major life history stages; at the time points of weaning, age at first reproduction and average life expectancy, long-lived primates and foxes have significantly fewer proliferating cells than rodents. Although the database for neuronal differentiation is limited, we find indications that the extent of neuronal differentiation is subject to species-specific selective adaptations. We conclude that absolute age is the critical factor regulating cell genesis in the adult hippocampus of mammals. Ontogenetic and ecological factors primarily influence the regulation of neuronal differentiation rather than the rate of cell proliferation.
成年海马神经发生是啮齿动物中的一个显著事件。在预期寿命较长的物种中，成年海马齿状回中新产生的细胞较少，或者完全不存在。有几条证据表明，成年神经发生的调节机制在短寿命和长寿命哺乳动物之间存在差异。在对比较不同物种相关因素和问题进行批判性评估后，我们提供了一个来自七种实验室品系小鼠（BALB、C57BL/6、CD1、远交系）和大鼠（F344、Sprague-Dawley、Wistar）以及六种其他啮齿动物物种（其中四种是野生来源的，即木鼠、田鼠、刺鼠和豚鼠）、三种非人类灵长类物种（狨猴和两种猕猴物种）和一种食肉动物（红狐）的定量比较。将增殖细胞的数量与总颗粒细胞数量归一化，我们观察到增殖呈整体指数下降，这种下降在物种和目之间是时间上相等的，与早期发育过程和寿命无关。长寿命和短寿命哺乳动物在主要的生活史阶段存在差异；在断奶、首次繁殖年龄和平均预期寿命的时间点上，长寿命的灵长类动物和狐狸的增殖细胞明显少于啮齿动物。尽管神经元分化的数据库有限，但我们发现有迹象表明，神经元分化的程度受到物种特异性选择适应的影响。我们得出结论，绝对年龄是调节哺乳动物成年海马体细胞发生的关键因素。个体发生和生态因素主要影响神经元分化的调节，而不是细胞增殖的速度。
