Department of Psychology and Neuroscience and Behavior Program Barnard College of Columbia University, New York, New York, USA.
Department of Psychology and Neuroscience and Behavior Program Barnard College of Columbia University, New York, New York, USA,
Dev Neurosci. 2019;41(1-2):132-138. doi: 10.1159/000502056. Epub 2019 Aug 20.
Adolescence is associated with significant reductions in hippocampal cellular proliferation and neurogenesis, the physiological and behavioral implications of which are unclear. Though sex differences exist in these proliferative processes in adulthood, relatively little is known about the role sex plays in these adolescent-related changes. To address this gap, we examined cross-sectional area of the dentate gyrus and cellular proliferation, as measured by Ki-67 immunohistochemistry, in pre- (30 days), mid- (45 days), and post-adolescent (70 days) male and female rats. We also investigated the number of immature neurons using doublecortin (DCX) immunohistochemistry in pre- and post-adolescent males and females. Despite increases in the size of the dentate gyrus during adolescence, we found significant adolescent-related decreases in hippocampal proliferation in both males and females, with a more dramatic decrease in males, indicating both age- and sex-dependent changes in the dentate gyrus. We also found an adolescent-related decline in the number of immature neurons in the dentate gyrus of male rats and a female-biased sex difference in the number of immature neurons in adults. Given these significant changes in the dentate gyrus, these data suggest that this period in development might be particularly sensitive to internal and external factors known to modulate neurogenesis, with potential sex-specific neurobehavioral ramifications.
青春期与海马体细胞增殖和神经发生的显著减少有关，其生理和行为影响尚不清楚。尽管成年后的这些增殖过程存在性别差异，但对于性别在这些与青春期相关的变化中所起的作用，人们知之甚少。为了解决这一差距，我们检查了雄性和雌性大鼠在青春期前（30 天）、中期（45 天）和青春期后（70 天）的齿状回横截面积和细胞增殖，用 Ki-67 免疫组化法测量。我们还在青春期前和青春期后的雄性和雌性大鼠中使用双皮质素（DCX）免疫组化来研究未成熟神经元的数量。尽管在青春期齿状回的大小增加，但我们发现雄性和雌性动物的海马体增殖都与青春期有关，雄性动物的减少更为明显，这表明齿状回存在年龄和性别依赖性的变化。我们还发现雄性大鼠齿状回中未成熟神经元的数量与青春期有关下降，而成年大鼠中未成熟神经元的数量存在雌性偏倚的性别差异。鉴于齿状回的这些显著变化，这些数据表明，这一发育阶段可能特别容易受到已知调节神经发生的内部和外部因素的影响，具有潜在的性别特异性神经行为后果。
