MacLusky Neil J, Thomas Gladis, Leranth Csaba
Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
Departments of Obstetrics and Gynecology, Yale University School of Medicine, New Haven, CT 06520-8063, USA.
Brain Res. 2017 Feb 15;1657:361-367. doi: 10.1016/j.brainres.2017.01.002. Epub 2017 Jan 4.
High dietary intake of plant estrogens (phytoestrogens) can affect brain structure and function. The effects of phytoestrogen intake within the range of normal animal and human dietary consumption, however, remain uncertain. The aim of the present study was to determine the effects of the isoflavonoids present in a standard low phytoestrogen laboratory rat chow on spine synapse density in the stratum radiatum of area CA1 of the hippocampus. Weanling rats (22days old) were fed either standard chow (Teklad 2018), a nutritionally comparable diet without soy (Teklad 2016) or a custom diet containing Teklad 2016 supplemented with the principal soy isoflavonoids, daidzein and genistein, for 40days. Rats were ovariectomized at 54days of age. Eight days later, spine synapse density on the apical dendrites of hippocampal pyramidal neurons in the stratum radiatum of area CA1 was measured by electron microscopic stereological analysis. Animals maintained on Teklad 2016 exhibited an approximately 60% lower CA1 spine synapse density than animals consuming Teklad 2018. Replacing genistein and daidzein in Teklad 2016 returned synapse density to levels indistinguishable from those in animals on Teklad 2018. These results indicate that the isoflavonoids in a standard laboratory rat diet exert significant effects on spine synapse density in the CA1 region of the hippocampus. Since changes in spine synapse density in this region of the hippocampus have been linked to cognitive performance and mood state, these data suggest that even relatively low daily consumption of soy phytoestrogens may be sufficient to influence hippocampal function.
高膳食摄入植物雌激素（phytoestrogens）会影响大脑结构和功能。然而，在正常动物和人类饮食摄入范围内的植物雌激素摄入影响仍不确定。本研究的目的是确定标准低植物雌激素实验室大鼠饲料中存在的异黄酮对海马体CA1区辐射层脊柱突触密度的影响。将断奶大鼠（22日龄）喂食标准饲料（Teklad 2018）、不含大豆的营养相当的饲料（Teklad 2016）或含有Teklad 2016并补充主要大豆异黄酮大豆苷元和染料木黄酮的定制饲料，持续40天。大鼠在54日龄时进行卵巢切除。八天后，通过电子显微镜立体分析测量CA1区辐射层海马锥体细胞顶端树突上的脊柱突触密度。食用Teklad 2016的动物的CA1脊柱突触密度比食用Teklad 2018的动物低约60%。在Teklad 2016中替换染料木黄酮和大豆苷元可使突触密度恢复到与食用Teklad 2018的动物无法区分的水平。这些结果表明，标准实验室大鼠饮食中的异黄酮对海马体CA1区的脊柱突触密度有显著影响。由于海马体该区域的脊柱突触密度变化与认知表现和情绪状态有关，这些数据表明，即使每天相对少量摄入大豆植物雌激素也可能足以影响海马体功能。
