Chen Li-Jin, Tseng Guo-Fang
Department of Anatomy, College of Medicine, Tzu Chi University, No. 701, Section 3, Zhongyang Rd., Hualien, 970374, Taiwan.
Biogerontology. 2025 Jan 20;26(1):41. doi: 10.1007/s10522-025-10186-2.
Aging women experience a significant decline of ovarian hormones, particularly estrogen, following menopause, and become susceptible to cognitive and psychomotor deficits. Although the effects of estrogen depletion had been documented in the prefrontal and somatosensory cortices, its impact on somatomotor cortex, a region crucial for motor and cognitive functions, remains unclear. To explore this, we ovariectomized young adult female rats and fed subsequently with phytoestrogen-free diet and studied the effects of estrogen depletion on the somato-sensory and motor cortices. Low serum estrogen was confirmed prior to biochemical and morphological analyses. Results revealed that estrogen depletion differentially affected the two cortical areas: all three estrogen receptors were downregulated in the somatosensory cortex, whereas in the somatomotor cortex, G-protein-coupled estrogen receptor 30 was upregulated, estrogen receptor α decreased, and estrogen receptor β remained unaffected. Intracellular dye injections revealed decreased dendritic spines on layer III and V pyramidal neurons of the somato-sensory cortex but increased in those of the motor cortex. These were accompanied by decrease and increase of excitatory postsynaptic density protein 95 respectively. Since dendritic spines receive excitatory inputs, these findings suggest that estrogen depletion changes the excitatory connectivity of the somato-sensory and motor cortices in opposite directions. Notably, estradiol replenishment reversed the dendritic spine increase in the somatomotor cortex, confirming the estrogen dependency of this effect. The differential influence of estrogen depletion on these two cortices could have contributed to the cognitive and psychomotor abnormalities in postmenopausal females.
绝经后，老年女性的卵巢激素，尤其是雌激素，会显著下降，并容易出现认知和精神运动功能缺陷。尽管雌激素耗竭在前额叶和体感皮层的影响已有文献记载，但其对躯体运动皮层（对运动和认知功能至关重要的区域）的影响仍不清楚。为了探究这一点，我们对年轻成年雌性大鼠进行卵巢切除术，随后喂食不含植物雌激素的饮食，并研究雌激素耗竭对躯体感觉和运动皮层的影响。在进行生化和形态学分析之前，确认血清雌激素水平较低。结果显示，雌激素耗竭对这两个皮层区域的影响不同：体感皮层中所有三种雌激素受体均下调，而在躯体运动皮层中，G蛋白偶联雌激素受体30上调，雌激素受体α减少，雌激素受体β不受影响。细胞内染料注射显示，体感皮层第III层和第V层锥体神经元的树突棘减少，而运动皮层的树突棘增加。这些变化分别伴随着兴奋性突触后致密蛋白95的减少和增加。由于树突棘接收兴奋性输入，这些发现表明雌激素耗竭使躯体感觉和运动皮层的兴奋性连接发生相反方向的变化。值得注意的是，雌二醇补充逆转了躯体运动皮层中树突棘的增加，证实了这种效应的雌激素依赖性。雌激素耗竭对这两个皮层的不同影响可能导致了绝经后女性的认知和精神运动异常。
