超细碳黑-多环芳烃复合颗粒物转运过程毒性机理的研究

It has become a critical scientific issue to clarify the biological toxic mechanism of ultrafine particles (UFPs) on the control and risk assessment of air pollution. There is some evidence suggesting that their observed toxic effects may be mainly due to the organic compounds adsorbed onto the carbonaceous core. However, because of the complex composition as well as the collection differences of samples, it is very difficult to elucidate the effects of absorbed components on the toxic mechanism of UFPs. In this study, stable ultrafine carbon black particles with one of the three typical PAHs were prepared to simulate the UFPs, and their toxic effects on human serum albumin (HSA) were investigated by means of multiple spectroscopic methods, gel electrophoresis as well as electron microscopy under simulative physiological conditions. And the effects of different absorbed PAHs on the particle-protein binding systems were also evaluated. Besides, we also examined the modification of HSA on the biological effects of vascular endothelial cells induced by these composite particles using the flow cytometry and enzyme activity testing techniques. This report provides basic data to quantitatively analyze the toxicity of the absorbed components in ultrafine particles during the transport process, and it will also complement studies on the risk assessment of UFPs on the human health.

阐明超细颗粒物（UFPs）对健康影响的毒理学机制已成为目前大气污染控制和风险评估的关键科学问题。UFPs碳核表面有机组分的不同决定了其毒性的差异，但因颗粒物的成分复杂且采集样品的不确定性，有关特征吸附组分对UFPs生物毒性效应的影响机制尚不明确。本课题拟以超细碳黑颗粒为核心，表面负载典型多环芳烃（PAHs）组分，制成三种复合颗粒物作为UFPs的毒性评价模型。在体外条件下利用多种光谱学手段、凝胶电泳和电镜技术系统考察三种复合颗粒物与人血清白蛋白（HSA）的相互作用机理，探讨不同PAHs组分对复合颗粒物与蛋白结合体系的毒性作用规律。另外通过流式细胞仪和酶活性测试等多种实验手段进一步研究HSA对复合颗粒物诱发血管内皮细胞生物学效应的调控机制。本课题为UFPs表面复杂吸附组分转运过程的生物毒性评价提供了重要的科学依据，有利于下一步深入开展UFPs对人群健康的风险评估工作。

阐明超细颗粒物（UFPs）在血液转运过程中的生物毒理学机制显得尤为重要。但由于UFPs的表面成分复杂且采集样品的差异性等限制因素的存在，有关UFPs上特征吸附组分的生物毒性作用仍缺乏深入研究。本课题以超细碳黑颗粒（UFCB）为核心，表面负载两种典型多环芳烃组分——菲（Phe）和芘（Pyr），制成了两种复合颗粒物作为UFPs的毒性评价模型。通过透射电镜和Zeta电位粒度分析仪观察发现，复合颗粒物的粒径约为5nm左右，颗粒稳定存在，且分散性良好。在体外条件下，以血液中含量最丰富的人血清白蛋白（HSA）作为靶蛋白，利用荧光光谱、紫外可见吸收光谱、同步荧光光谱、圆二色谱和等温量热滴定等技术考察发现，两种复合颗粒物通过疏水作用与HSA发生多位点的结合，均能使蛋白的骨架变得松散，二级结构变化明显，导致蛋白分子中芳香族氨基酸残基的微环境发生改变，并对HSA的生物活性造成影响，其中超细碳黑-菲复合颗粒（UFCB-Phe）对蛋白的毒性效应较超细碳黑-芘（UFCB-Pyr）更为显著。在进一步的细胞实验中，通过酶活性测试、荧光显微镜等多种实验手段研究了两种特征复合颗粒对A549细胞抗氧化能力的影响。研究发现，UFCB-Phe和UFCB-Pyr均能诱发A549细胞中多种生物标志物如谷胱甘肽（GSH）、丙二醛（MDA）、活性氧（ROS）的含量以及超氧化物歧化酶（SOD）和过氧化氢酶（CAT）的活性发生改变，诱发细胞的氧化应激效应。另外，牛血清白蛋白（BSA）的加入减弱了两种复合颗粒物诱发A549细胞的氧化损伤效应。本研究为定量探寻UFPs 表面复杂吸附组分的生物毒性提供了重要的基础数据和新的研究思路，也为疾病的早期诊断、预防和治疗也提供了重要的前提，同时在加强大气颗粒物污染的防治和保护人类健康方面具有重要的指导意义。