丙戊酸钠联合雌激素通过影响雌激素受体对去卵巢痴呆小鼠的作用及机制研究

Previous studies have demonstrated that estrogens, a group of steroid compounds, confers neuroprotection against toxicity of amyloid βpeptide(Aβ) and exert a preventional and protective role in Alzheimer's disease (AD) development. However, Estrogen replacement therapy (ERT) initiated after menopause are proved ineffectiveness, the possible underlying mechanism may be related to the significantly decreased level of estrogen receptors(ERs) and ERα/ERβ ratio. Therefore, up-regulating ERs levels is an potential method in treating menopause AD patients. Glycogen synthase kinase-3β (GSK-3β) is another key player in AD. Increased GSK-3β activity in the brain can induce hyperphospharylation of tau, as well as Abeta generation and deposition, furtherly damage neuron and disturb neurogenesis, which is one of the key pathogenesis of Alzheimer's disease. Therefore, inhibition of GSK-3β may be beneficial to prohibit the progress of Alzheimer's disease. Valproic acid (VPA) is first-line anticonvulsant agents for treating epilepsy and bipolar disorder. Recent studies showed that VPA is a selective GSK-3β inhibitor, but whether VPA has neuroprotective effect on AD is still unknown. Our previous studies systematically explored the effect of VPA on AD. Our data showed that VPA treatment significantly improved memory deficits, significantly decreased neuritic plaque formation and increased number of neuronal cell bodies and processes in the brain of AD model mice, our recent preliminary study showed that VPA can also upregulates ERα and ERβ levels, which indicates that VPA has potential protective effect on AD, but this protective effect of VPA on male AD model mice is better than that on female one due to low estrogen level in the brain of female AD model mice. Based on previous studies, the present study is designed to examine the effect of VPA combined with estrodiol on ovariectomized AD model mice and its possible underlying mechanism, by using VPA and estrodiol treatment to cells and APP/PS double transgenic AD model mice, assisted with various techniques, such as behavioral test, morphological test, physiological test, cellular and molecular biological methods. The outcome of this study may not only provide an experimental basis to develop and design multi-target-directed drugs to prevent and treat multi-factorial neurodegenerative AD, but also provide a strong evidence to implemting individiualized treatment program to gender-difference disease(such as AD).

雌激素是防治阿尔茨海默病（ AD）的有效药物，但对绝经后AD患者无效，其分子机制源于AD患者脑内雌激素受体(ERα/ERβ)比例下调所致，上调脑内ERs水平有望提高对绝经后AD患者的疗效；GSK-3β活性异常是促进AD发生发展的另一重要危险因素，申请人前期工作发现临床一线抗癫痫药丙戊酸钠(VPA)可通过抑制GSK-3β活性对痴呆小鼠起保护作用，预实验还发现VPA可上调ERs的表达，但因雌性痴呆小鼠脑内雌激素处于低水平，导致VPA对雌性AD模型小鼠的保护作用不理想。为此，本实验拟用VPA和雌激素共同处理去卵巢AD模型小鼠和细胞，结合行为学、形态学、电生理学、细胞和分子生物学等技术，深入探讨联合用药对雌性AD模型小鼠的防治效果，并阐明其有效作用机制。本项目不仅为研究和开发多靶向药物防治AD这一多因异质性疾病提供了实验室依据，同时对这种具有性别差异的疾病实施个性化治疗方案提供了强有力的证据。

雌激素是防治阿尔茨海默病(AD)的有效药物，但对绝经后AD患者无效，其分子机制源于AD患者脑内雌激素受体(ERs)表达下调所致，上调脑内ERs表达有望提高对绝经后女性AD患者的疗效；GSK-3β活性异常是引起AD发生发展的另一重要危险因素，申请人前期工作发现丙戊酸钠(VPA)可通过抑制GSK-3β活性对痴呆小鼠起保护作用，但因雌性痴呆小鼠脑内雌激素处于低水平，而致VPA对雌性痴呆小鼠的保护作用不显著。本课题采用双侧卵巢切除（OVX）建立绝经模型的基础上，应用行为学、形态学、细胞和分子生物学等技术探讨VPA联合雌激素对绝经晚期AD是否具有保护作用。本课题第一部分检测了雌激素缺乏对AD小鼠脑内雌激素及受体和GSK-3β的影响，实验结果发现，OVX早期雌激素缺乏对小鼠脑内病理变化和认知功能障碍的影响尚不显著；但随着OVX时间延长，脑内长期的低水平雌激素和紊乱的雌激素受体比例可通过影响自噬-溶酶体系统和ERβ/IGF-1R/GSK-3β信号通路加重小鼠脑内的病理改变、加重认知功能的损害。第二部分检测了VPA联合雌激素对绝经晚期AD模型小鼠的保护作用及相关机制，实验结果发现，联合用药可通过影响Aβ的产生和降解,也可通过抑制GSK-3β活性及恢复ERα/ERβ比例来增强ER对雌激素的敏感性，从而对绝经晚期AD发挥保护作用。本课题发表论著12篇，SCI收录6篇；新获国家自然科学基金2项。本研究不仅为研究和开发多靶向联合用药防治AD提供了理论基础和实验依据，同时对这种具有性别差异的疾病实施个性化治疗方案提供了强有力的证据，具有重要的应用价值。