PM2.5致人类胚胎停育的氧化应激及炎症反应机制研究

We recently reported that maternal PM2.5 exposures during the post-conception period could increase the risk of human clinically recognized early pregnancy loss. The mechanisms underlying this association are not yet clear. Oxidative stress and inflammation are the main hypothesized mechanisms of respiratory and cardiovascular diseases caused by PM2.5. Whether these also mediate the effects of PM2.5 on embryonic development remains to be studied. Using our previously developed temporally-adjusted land use regression PM2.5 models and the advantages of clinical case-control recruitment and biological sample collection, we intend to conduct human biomarker studies and human cytotoxicity experiments on our basis of pre-experiment. Selected biomarkers in serum and chorionic villous tissue (the precursor tissue of placenta) will be measured in early pregnancy loss cases and normal early pregnancy controls. In the epidemiological study, associations between PM2.5 exposure and biomarkers of both systemic and local (at the maternal-fetal interface) oxidative stress and inflammation will be investigated. Further, PM2.5 samples from different periods (heating/non-heating period) and different sources (traffic/industrial source) will be collected. These samples will be used in experiments using human chorionic trophoblast cells to assess the effects of PM2.5 and PM2.5 chemical components on cellular oxidative stress and inflammation, and to screen for especially toxic chemical components that inhibit cellular function. This project will provide insight into the mechanisms underlying PM2.5-induced human early pregnancy loss at the maternal, tissue and cellular levels. It will also contribute to providing a scientific basis for interventions to prevent adverse pregnancy outcomes.

项目组前期环境流行病学研究发现，母体受孕后的PM2.5暴露可增加人类胚胎停育的发生风险，机制未明。氧化应激及炎症反应是PM2.5致呼吸和心血管疾病的主要机制，是否也介导了PM2.5对胚胎发育的影响有待研究。项目拟依托时间调整土地利用回归模型研究积累、临床一线的病例-对照招募和生物样本采集优势，在预实验基础上开展人体生物标志物检测和人源细胞毒理学实验。测定胚胎停育和正常早孕人群血清及绒毛组织的代表性生物标志物含量，分析PM2.5诱发妊娠早期全身性和母胎界面氧化应激及炎症反应的剂量-效应关系。采集采暖期/非采暖期、交通源/工业源的PM2.5样品，进行人绒毛膜滋养层细胞染毒和干预实验，探索PM2.5及化学组分对细胞氧化应激及炎症反应的影响，筛选出抑制细胞增殖、迁移和侵袭能力的高危化学组分。从母体、组织和细胞水平揭示PM2.5引起人类胚胎停育的效应机制，为采取干预措施预防不良妊娠结局提供科学依据。

课题组前期研究发现，孕期环境PM2.5暴露可增加人类胚胎停育的发生风险。为进一步探索其暴露效应机制，本项目开展了一系列基于母体全身性和母胎界面生物标志物的研究。采用时间调整土地利用回归模型估算早孕妇女在孕期若干暴露时间窗的住址点位每日PM2.5浓度，在国内外首次评估了环境PM2.5暴露对早孕妇女血清和胎盘绒毛组织的氧化应激及炎症反应标志物的影响。研究发现，血清样本采集前若干天的PM2.5暴露可诱发早孕妇女全身性的氧化性蛋白质损伤、脂质过氧化、抗氧化应答和炎症反应，使血清3-硝基酪氨酸（3-NT）、丙二醛（MDA）、总抗氧化能力（T-AOC）以及炎症细胞因子白细胞介素1β（IL-1β）、白细胞介素6（IL-6）和肿瘤坏死因子-α（TNF-α）升高；胚胎停育组与正常早孕组相比，PM2.5相关的母体氧化性蛋白质损伤、脂质过氧化和炎症更明显，且抗氧化反应不足。围排卵期和绒毛样本采集前若干天的母体PM2.5暴露可引起早孕胎盘绒毛的炎症反应和氧化性DNA损伤，使绒毛炎症细胞因子和8-羟基脱氧鸟苷（8-OHdG）水平升高，且PM2.5相关的绒毛DNA损伤在采暖期比非采暖期更严重；胚胎停育组与正常早孕组相比，PM2.5相关的绒毛炎症和DNA损伤更严重。佩戴口罩可能对PM2.5暴露相关的蛋白质损伤起到潜在的预防作用。我们还在国内外首次对母体孕期环境PM2.5暴露与足月出生体重（TBW）的关联进行了系统评价和荟萃分析，发现孕期包括妊娠早期的环境PM2.5暴露可降低TBW，且即使PM2.5浓度低于10 µg/m3时仍有负性影响。研究提示，PM2.5相关的母体全身性和母胎界面氧化应激及炎症反应可能参与了人类胚胎停育的发病机制，并对后续妊娠结局有一定影响。本项目为采取相应的孕期PM2.5暴露防护及抗炎、抗氧化干预措施提供了科学依据，从而预防不良妊娠结局和胎儿源性成人期疾病，保护公众健康。