Department of Biology, Middlebury College, McCardell Bicentennial Hall, Middlebury, VT 05753, USA; Program in Neuroscience, Middlebury College, McCardell Bicentennial Hall, Middlebury, VT 05753, USA.
Department of Biology, Middlebury College, McCardell Bicentennial Hall, Middlebury, VT 05753, USA.
Neuroscience. 2017 Sep 30;360:155-165. doi: 10.1016/j.neuroscience.2017.07.046. Epub 2017 Jul 28.
Past research indicates that female meadow voles (Microtus pennsylvanicus) show decreased neurogenesis within the hippocampus during the breeding season relative to the non-breeding season, whereas male voles show no such seasonal changes. We expanded upon these results by quantifying a variety of endogenous cell proliferation and neurogenesis markers in wild-caught voles. Adult male and female voles were captured in the summer (breeding season) or fall (non-breeding season), and blood samples and brain tissue were collected. Four cellular markers (pHisH3, Ki67, DCX, and pyknosis) were labeled and then quantified using either fluorescent or light microscopy. The volume of the cell layers within the dentate gyrus (hilus and granule cell layer) was significantly larger in males than in females. In both sexes, all the cellular markers decreased significantly in the dentate gyrus during the breeding season relative to the non-breeding season, indicating decreased cell proliferation, neurogenesis, and pyknosis. Only the pHisH3 marker showed a sex difference, with females having a greater density of this cell proliferation marker than males. During the breeding season relative to the non-breeding season, males and females showed the predicted significant increases in testosterone and estradiol, respectively. Overall, these results suggest higher levels of neuronal turn-over during the non-breeding season relative to the breeding season, possibly due to seasonal changes in sex steroids.
过去的研究表明，与非繁殖季节相比，繁殖季节的雌性草原田鼠（Microtus pennsylvanicus）的海马体中的神经发生减少，而雄性田鼠则没有这种季节性变化。我们通过量化野生捕获的田鼠中的各种内源性细胞增殖和神经发生标志物来扩展这些结果。成年雄性和雌性田鼠在夏季（繁殖季节）或秋季（非繁殖季节）被捕，采集血液样本和脑组织。使用荧光或明场显微镜对四种细胞标志物（pHisH3、Ki67、DCX 和固缩）进行标记和定量。齿状回（门区和颗粒细胞层）的细胞层体积在雄性中明显大于雌性。在两性中，所有细胞标志物在繁殖季节的齿状回中的表达均显著低于非繁殖季节，表明细胞增殖、神经发生和固缩减少。只有 pHisH3 标志物表现出性别差异，雌性的这种细胞增殖标志物密度高于雄性。与非繁殖季节相比，繁殖季节的雄性和雌性的睾丸酮和雌二醇水平分别显著增加。总体而言，这些结果表明非繁殖季节的神经元更替水平高于繁殖季节，这可能是由于性激素的季节性变化。
