活性氧介导的胎盘内质网应激在1-硝基芘诱发胎儿生长受限中的作用

Increasing number of studies have shown associations between maternal exposure to PM2.5 during pregnancy and adverse birth outcomes, particularly low birth weight (LBW). Additional mechanistic studies are needed to understand the underlying mechanisms for this association. Investigating the specific toxin of importance in PM2.5 is crucial to understand the biological mechanisms in the area of PM2.5 and birth outcomes. Nitrated polycyclic aromatic hydrocarbons (NPAHs) are typical pollutants in PM2.5 and signature components of diesel exhaust particles (DEPs). The aim of the present study is to investigate the effects of the major NPAH, 1-NP, in fetal growth restriction and the potential pathways involved. Inhibitors of metabolic enzymes are used to explore the role of metabolism in 1-NP induced oxidative stress in placental cells. And this study is to investigate whether antioxidant could downregulate placental unfolding protein responses to explore the role of ROS in 1-NP caused placental endoplasmic reticulum stress. Also, inhibitors of endoplasmic reticulum stress and siRNAs for different unfolding protein response pathways are applied to explore the impact of ROS mediated endoplasmic reticulum stress in placenta injury and fetal growth restriction. This study will explain the developmental toxicity of PM2.5 and provide the toxicologic data for PM2.5 control.

孕期PM2.5暴露与低出生体重有关，但机制不明。PM2.5中含多种有毒物质，硝基多环芳烃(NPAHs)是PM2.5中的高毒性组分，也是柴油机尾气颗粒的标志性污染物。本课题以1-硝基芘(1-NP)这一典型NPAHs为研究对象，通过检测1-NP暴露对胎盘和胎鼠生长的损害作用，确认其发育毒性；通过检测不同代谢酶抑制剂对1-NP引起胎盘细胞氧化应激的拮抗作用，阐明代谢过程在1-NP引起胎盘细胞ROS产生中的作用；通过检测抗氧化剂对1-NP诱发胎盘细胞非折叠蛋白反应的拮抗效应，阐明ROS在1-NP诱发胎盘内质网应激中的作用；利用内质网小分子伴侣和siRNA干扰技术抑制内质网应激，观察内质网应激抑制对1-NP所致胎盘细胞损伤和胎儿生长受限的拮抗作用，阐明ROS介导的内质网应激在1-NP致胎儿生长受限中的作用。该项目可在一定程度上阐明PM2.5的发育毒性机制并为制定PM2.5的控制政策提供毒理学依据。

孕期PM2.5暴露与胎儿生长受限（intra-uterine growth restriction, IUGR）等多种不良妊娠结局有关，但机制不明。1-硝基芘（1-nitropyrene, 1-NP）是PM2.5中的关键毒性组分，孕期 1-NP 暴露可能在PM2.5诱发IUGR中起重要作用。本研究利用动物实验结合细胞实验，深入探讨了孕期1-NP暴露与IUGR之间的关系及其潜在作用机制。结果显示：（1）1-NP诱发IUGR具有暴露时期和剂量依赖性，孕晚期暴露可引起胎数体重和顶臀长的显著降低，诱发IUGR，且与胎盘的发育受损有关。（2）孕晚期1-NP暴露可引起孕鼠胎盘血窦区域的减少、胎盘迷路层细胞增殖抑制、胎盘氧化应激和内质网应激，但不引起胎盘迷路层细胞凋亡; 体外细胞暴露实验同样证实1-NP不引起人胎盘绒毛膜滋养细胞HTR8/Svneo的凋亡，但引发细胞增殖抑制和细胞周期阻滞，同时还引起胞内ROS增加、加重DNA损伤和激活遗传毒性应激通路。（3）抗氧化剂PBN预处理HTR8/SVneo细胞，可以改善1-NP引发的遗传毒性应激、细胞周期阻滞和增殖抑制，抗氧化剂NAC预处理孕鼠，可以减轻1-NP诱导的胎盘增殖抑制作用、胎盘发育受损和胎鼠的IUGR，提示ROS介导的遗传毒性应激在1-NP诱发胎盘损伤及IUGR中有重要作用。本项目在一定程度上阐明1-NP这一PM2.5关键毒性组分的发育毒性及作用机理，并对PM2.5的控制提供毒理学依据。