丘脑网状核PTCHD1介导宫内双酚A,妊娠压力联合暴露致婴幼儿认知功能受损的机制研究

Bisphenol A, a xenoestrogen, is ubiquitously in environment. Maternal stress induced maternal cortical hormone releasing. The intrauterine exposure of bisphenol A and pregnancy stress have joint neurotoxicity effect. However, the epidemiological studies is lack and pathogenic mechanism is unknown. Based on the in vitro experiment basis, the PTCHD1 expression was inhabited by the combined exposure of BPA and corticosterone. PTCHD1 (Patched-domain containing protein 1), expressed in thalamic reticular nucleus, is a new candidate molecules of cognitive function. Owning to unique structure of steroid induced domain (steroid- sensitive domain, SSD) in PTCHD1, we hypothesis that bisphenol A and glucocorticoids may interact with SSD, lead to PTCHD1 expression decreased, resulted in the impairment of learning and memory. (1) Based on existing longitudinal birth cohort of BPA exposure, we plan to investigate the association between the joint exposure of pregnant bisphenol A, maternal stress and the infants’ cognitive function in 24 months. (2) We would construct the joint exposure animal model of bisphenol A and pressure, and then examine the cognitive toxicology effect of PTCHD1 expression, synaptic plasticity in aspect of the behavior, anatomy, electrophysiology, and molecular biology, respectively. This study would provide the evidence for multifaceted protective interventions to cognitive function of pregnant mothers and their children.

双酚A广泛存在于环境，具有类雌激素作用；妊娠压力促进母体糖皮质激素分泌增多，宫内双酚A和妊娠压力对胎儿神经毒性具有联合叠加作用，但缺乏人群学研究，且致病机制不明。基于体外实验依据，双酚A和皮质酮染毒神经元细胞株PTCHD1蛋白显著下降。PTCHD1（补丁结构包含蛋白）在丘脑网状核表达，是新兴认知功能候选分子，且PTCHD1含类固醇感应结构域（steroid-senstive domain, SSD），故我们认为：双酚A、糖皮质激素与SSD结构域相互作用，下调PTCHD1表达，导致认知功能受损。基于课题组已开展母婴双酚A暴露系列研究 ① 纵向调查宫内双酚A和妊娠压力联合暴露与婴幼儿24个月认知功能的病因关系。 ② 构建双酚A和压力束缚联合暴露模型，从行为学、解剖、电生理、分子生物学等多角度观察幼鼠PTHCD1表达、突触可塑性等神经毒理效应，本课题实施将为婴幼儿认知功能防治提供依据。

研究目的:本研究拟通过人群学数据和动物学行为试验分析妊娠期尿双酚A浓度和脐带血皮质醇浓度联合暴露对子代24个月认知发育功能关联，并阐明PTCHD1是否作为双酚A和妊娠压力介导神经认知功能缺陷的桥梁蛋白之一。 .研究方法：基线数据库为一项共1085名孕妇的前瞻性出生队列，采用HPLC-MSMS方法测定妊娠晚期尿液双酚A浓度，采用生化法测定脐带血皮质醇浓度，采用年龄发育进程第三版问卷(ASQ-3)对2岁儿童进行认知发育评估。采用腹膜腔下注射双酚A方法进行孕鼠双酚A染毒（G7-G21），低中高梯度浓度分别为5ug/kg. day、50ug/kg.day、500ug/kg.day，采用慢性不可预知性压力应激模型进行孕鼠压力造模。在仔鼠出生后21天始采用糖水偏好试验，旷场试验，Morris水迷宫试验分析仔鼠焦虑抑郁状态和学习记忆功能。采用基因蛋白定量方法测定仔鼠海马组织PTCHD1和PSD95表达量改变。 .研究结果: 共纳入符合条件共510母子对，在母-女婴儿对中，母亲妊娠期高浓度BPA与子代粗大运动能区 [-5.1 (95% CI: -8.6, -1.4, p=0.01)]和解决问题能区 [-4.1 (95% CI: -7.6, -0.5, p=0.01)]显著负相关，母-男婴儿对中未发现显著相关性。脐带血皮质醇高浓度组与子代男孩粗大运动能区[β=-5.7, (95% CI:-13.8，-2.9), p=0.01]，个人-社会能区[β=-5.3, (95% CI: -9.5,-0.6)，p=0.03]得分显著负相关，与女孩粗大运动能区[β=-5.4, (95% CI: -11.3, -2.1)，p=0.02]得分显著负相关。在双酚A皮质醇联合暴露模型中，高浓度双酚A高浓度皮质醇组与女孩粗大运动能区相关性最显著[β=-6.5, (95% CI: -8.3, -0.3), p=0.01]。在孕鼠双酚A联合慢性不可预见性应激模型中，双酚A高浓度和压力应激组也表现为蔗糖偏好率显著降低，旷场试验中中央格子静止时间显著增加，跨格子数目显著减少，Morris水迷宫中逃避潜伏期显著延长，探索平台时间显著降低，海马组织中PTCHD1和PSD95基因和蛋白表达量均显著增加。.研究结论: 生命早期高浓度双酚A暴露，过多妊娠压力暴露与婴幼儿认知发育落后具有显著关联，是影响脑发育健康的环境病因，