微塑料对人体肠道毒性及屏障干扰作用的体外模型研究

With frequent detection of microplastics in area of human activity, investigation of microplastics on human health is becoming increasingly needed. Microplastics may have the access to gastrointestinal tract through food chain, which is an important way for human exposure. Since it is difficult for microplastics to get into internal recycle, intestine have become target organ of microplastics. It has been reported that microplastics could induce intestine inflammation and disturb efflux function in aquatic organisms. However, potential risks of microplastics on human intestine have not been documented yet. Through initial exploration, we found that cell apoptosis was induced by exposure of microplastics in Caco-2 cell line. Therefore, further research is needed to figure out intestine toxicity and barrier interference induced by microplastics. In this project, polystyrene microplastics is picked as the research object. We intend to build in vitro intestinal transport model with Caco-2 cell line and apply the model in the following study. Toxicity assay, chemical analysis and omics approach will be used to study intestine toxicity of microplastics and underlying mechanisms; Effects of microplastics on physical and biological barrier of intestine will be investigated to clarify influence of microplastics on human intestine transport function; Moreover, given that in real scenario, microplastics are often accompanied with heavy metals, we will investigate the influence of microplastics on bio-availability of typical heavy metals (such as Arsenic and Lead) in intestine and figure out underlying mechanisms. The results of this project will provide scientific basis and theoretical guidance for human health risk assessment of microplastics.

随着微塑料在人类活动区域的频繁检出，针对其人体健康风险研究的必要性日渐凸显。食物链是微塑料人体暴露的主要途径之一。由于难以进入体内循环，肠道成为微塑料的重要作用器官。已有研究证实，微塑料可诱导水生生物肠道细胞炎症损伤并破坏肠道外排功能，但微塑料对人体肠道的潜在风险尚无报道。基于申请人前期发现微塑料可诱导人肠道细胞凋亡的初步研究结果，本项目拟开展微塑料对人体肠道毒性及屏障干扰的研究。选取聚苯乙烯微塑料为研究对象，采用人源细胞Caco-2建立人体肠道转运体外模型，基于毒性检测、化学分析及生物组学技术相结合的方法，系统考察微塑料对人体肠道的毒性效应和致毒机制；从物理学屏障和生物学屏障角度，详细探讨微塑料对人体肠道吸收转运功能的影响；针对环境中微塑料多与重金属污染物共存的现状，深入揭示微塑料对砷、铅等典型重金属生物有效性的影响及相关机制。本项目将为微塑料的人体健康风险评估提供科学依据和理论支撑。

随着微塑料在不同环境介质中的频繁检出，针对其人体健康风险研究的必要性日渐凸显。肠道是吸收营养物质的重要部位，同时也是微塑料在生物体的重要蓄积器官。目前国内外针对微塑料的毒性效应已开展许多有意义的研究，但其对人体肠道影响的深入解析、对共存污染物经肠道转运的影响仍有待进一步探讨。.本项目以100 nm和5 μm两种粒径的聚苯乙烯微塑料（PS-MPs）为研究对象，以肠细胞为靶细胞，借助肠道转运经典体外模型，在考察PS-MPs对人结肠腺癌Caco-2细胞急性毒性的基础上，利用生物组学技术，从细胞水平和分子水平上阐明了PS-MPs暴露对人体肠道的毒性效应和相关机制；基于Caco-2细胞单层模型，明确了PS-MPs对肠道转运功能的影响；采用活体动物暴露方式，进一步分析了PS-MPs与有毒重金属对斑马鱼肠道的联合毒性和屏障功能的潜在风险，比较了体外细胞模型的毒性与活体动物之间的差异性。.项目严格按照预期目标和内容开展。研究结果揭示了不同粒径的PS-MPs可被Caco-2细胞摄入，降低细胞线粒体膜电位，抑制质膜ABC转运蛋白活性。PS-MPs可影响斑马鱼肠道化学免疫，导致肠道内致病菌丰度增加，且其毒性效应与其粒径大小密切相关。在单细胞水平，M1巨噬细胞是PS-MPs毒性作用的靶细胞，对免疫细胞的毒性表现出明显的粒径依赖效应。斑马鱼活体实验和Caco-2细胞transwell成膜实验的结果揭示了PS-MPs与共存污染物联合暴露对肠道物理屏障有恶化作用，相对于砷单独暴露，100 nm PS-MPs和砷联合暴露显著增加了对Caco-2单层细胞膜的毒性，而体外消化过程消除了PS-MPs诱导的毒性增敏效应。本项目的研究结果为微塑料的环境健康危害识别提供了科学基础。