海马神经发生在高龄妊娠子代脑功能障碍中的作用及机制研究

With the implementation of the “two child policy”, how to prevent and treat the related diseases of offspring of advanced maternal age(AMA) is a common concern of both medicine and society. Based on the clinical phenomenon of the high prevalence of chronic brain dysfunction diseases such as mental retardation, autism and epilepsy in offspring of AMA and early studies of our research team indicate that cognitive and emotional development and social capacity defects and expression of BDNF was decreased in offspring of AMA rats compared with the control group ,and meanwhile BDNF can promote neural stem cells functionally mature, proliferate, differentiate into nerve cells and promote the formation of synapses. We further establish the animal model of the offspring of AMA, combined with in vivo and in vitro neural stem cell culture and in the main line of AMA-BDNF gene methylation-hippocampal neurogenesis-immature brain development. From the gene and molecular level to the whole level, from morphology to function Level, to explore whether there is abnormal methylation of BDNF gene in offspring of AMA; to elucidate whether offspring brain dysfunction is related to abnormal hippocampal development; to study the main signal pathways of BDNF regulation in hippocampal neurogenesis and after the targeted intervention in different key links, to observe whether the brain dysfunction of offspring can be prevent and alleviated.The goal is to provide an possible way to improve the offspring brain function and the quality of AMA offspring life .It has a positive meaning to improve the overall quality of the population.

随着国家二孩政策的全面开放，如何防治高龄产妇子代的相关疾病，是医学和社会共同关注的问题。本项目针对临床上高龄妊娠子代智力低下、孤独症、癫痫等脑功能障碍性疾病发生率高的现象，在前期发现高龄孕鼠子代学习、记忆、情感及交往能力下降，同时伴有海马BDNF蛋白表达降低，而BDNF能够促进神经干细胞功能成熟、增殖、分化为神经细胞、促进突触形成的基础上，进一步建立高龄孕鼠动物模型，结合在体实验和体外神经干细胞培养，以高龄妊娠-BDNF甲基化-海马神经发生-未成熟脑发育为主线，从基因、分子到整体水平，从形态到功能层面，探索高龄妊娠子代是否存在BDNF基因甲基化异常，子代脑功能障碍是否与海马发育异常有关？研究BDNF调控子代海马神经发生的主要信号通路；观察在不同关键环节上针对性干预后，能否防治高龄妊娠子代脑发育障碍和功能异常。为改善高龄子代脑功能和生活质量，提供可能途径；对提高人口整体素质，具有积极意义。

随着“二孩政策”开放实施，35岁以上女性生育需求不断增加，高龄妊娠现象将更为突出。研究表明高龄妊娠子代更易患神经发育障碍疾病，但其导致脑功能障碍的机制尚不明确。探索高龄妊娠子代脑功能的发病机制和关键环节，有助于合理预防与干预，减轻家庭和社会负担。本研究在证实高龄妊娠子代存在认知、情绪及社会交往方面异常的基础上，结合未成熟脑发育特点，从表观遗传学与神经发育的角度，对比观察高龄妊娠与适龄妊娠子代发育期海马区神经干细胞的增殖、分化及突触、髓鞘的形成情况；研究神经发生关键信号通路BDNF/TrkB/ CREB与Notch1/Hes1信号通路的表达变化；明确高龄妊娠子代海马整体甲基化水平及DNA甲基转移酶的表达情况；探索去甲基化干预及维生素C干预对高龄妊娠子代的脑发育保护作用。结果发现，与适龄子代相比，高龄妊娠子代发育期海马区神经干细胞存在增殖、分化、成熟障碍；高龄子代发育期海马区神经细胞凋亡和自噬增加，并伴有髓鞘、突触发育障碍及成熟延迟；高龄妊娠子代海马神经发生重要信号通路BDNF/ TrkB/CREB，Notch1/Hes1部分重要节点分子表达水平异常；高龄妊娠子代海马区整体DNA甲基化表达水平升高，甲基化转移酶表达紊乱，BDNF启动子区域少量位点存在甲基化差异；通过去甲基化干预，可提高原代海马神经干细胞Notch1/Hes1信号通路的表达，减轻高龄妊娠对子代神经发生的影响；通过维生素C干预，可降低DNA甲基化水平，改善高龄妊娠子代髓鞘形成障碍，促进髓鞘形成和成熟。本研究结果提示，高龄妊娠可导致子代海马神经发生异常及脑功能障碍。高龄妊娠子代海马中神经发生重要信号通路BDNF/ TrkB/CREB，Notch1/Hes1部分重要节点分子表达水平异常。异常DNA甲基化在高龄妊娠导致子代脑功能障碍中发挥重要作用。去甲基化干预及维生素C干预可通过降低DNA甲基化水平从而改善高龄妊娠子代脑发育情况，可能有助于修复高龄妊娠所致子代脑功能障碍。