Thyroid hormones are critical for the regulation of development and differentiation of neurons and glial cells in the central nervous system (CNS). We have previously reported the sex-dependent changes of glial morphology in the brain under the state of hyperthyroidism. Here, we examined sex-dependent changes in spine structure of granule neurons in the dentate gyrus of hippocampus in male and female mice with hyperthyroidism. Using FIB/SEM (focused ion beam/scanning electron microscopy), three-dimensional reconstructed structures of dendritic spines in dentate granule cells were analyzed. Dendritic spine density in granule cells increased significantly in both male and female mice with hyperthyroidism. The decrease in spine volume was observed only in female mice. These findings suggest that hyperthyroidism induces the formation of spines with normal size in male mice but the formation of spines with small size in female mice. To evaluate an outcome of neuronal and previously observed glial changes, behavioral tests were performed. Male mice with hyperthyroidism showed increased locomotor activity in the open field test, while female mice showed elevated immobility time in the tail suspension test, reflecting depression-like behavior. Although direct link between changes in spine and behavioral modifications requires further analysis, our results may help to understand gender-dependent neurological and psychological symptoms observed in patients with hyperthyroidism.

甲状腺激素对于调节中枢神经系统（CNS）中神经元和神经胶质细胞的发育和分化至关重要。我们先前曾报道甲亢状态下大脑胶质细胞形态的性别依赖性变化。在这里，我们检查了甲状腺功能亢进的雄性和雌性小鼠海马齿状回中颗粒神经元的脊柱结构的性别依赖性变化。使用FIB / SEM（聚焦离子束/扫描电子显微镜），分析了齿状颗粒细胞中树突棘的三维重建结构。甲状腺功能亢进的雄性和雌性小鼠的颗粒细胞中树突棘密度显着增加。仅在雌性小鼠中观察到脊柱体积的减少。这些发现表明甲状腺功能亢进诱导雄性小鼠中正常大小的棘形成，而雌性小鼠中小型的棘形成。为了评估神经元和先前观察到的神经胶质变化的结果，进行了行为测试。甲状腺功能亢进的雄性小鼠在野外试验中显示出自发活动增加，而雌性小鼠的尾部悬吊试验中显示出不动时间增加，反映出抑郁样行为。尽管脊柱变化和行为改变之间的直接联系需要进一步分析，但我们的结果可能有助于了解甲状腺功能亢进症患者中观察到的性别依赖性神经和心理症状。为了评估神经元和先前观察到的神经胶质变化的结果，进行了行为测试。甲状腺功能亢进的雄性小鼠在野外试验中显示出自发活动增加，而雌性小鼠的尾部悬吊试验中显示出不动时间增加，反映出抑郁样行为。尽管脊柱变化和行为改变之间的直接联系需要进一步分析，但我们的结果可能有助于了解甲状腺功能亢进症患者中观察到的性别依赖性神经和心理症状。为了评估神经元和先前观察到的神经胶质变化的结果，进行了行为测试。甲状腺功能亢进的雄性小鼠在野外试验中显示出自发活动增加，而雌性小鼠的尾部悬吊试验中显示出不动时间增加，反映出抑郁样行为。尽管脊柱变化和行为改变之间的直接联系需要进一步分析，但我们的结果可能有助于了解甲状腺功能亢进症患者中观察到的性别依赖性神经和心理症状。