PM2.5细颗粒毒性机制研究

Increase in concentration of particulate matter of 2.5 microns or less (PM 2.5) is the main reason for the increasing urban air pollution. Recently, PM2.5 has been added to the routine air quality evaluation standards by the Ministry of Environmental Protection of China. However, it is still not very clear about how PM2.5 affects the human health, as well as the detailed toxicity mechanism of PM2.5. In this project, based on the characteristics of PM 2.5 including small size, large specific surface area and high adsorption activity, we propose that PM2.5 absorb a lot of toxic components in the atmosphere which can move deep into the lungs through inhalation, and then penetrate the lung into the blood stream, causing serious damage to lung or other health issues. Considering the complexity of the sources and composition of PM2.5, carbon nanoparticles including nano carbonblacks and nanodiamonds are used as simplified models of PM2.5. The adsorption of two main types of atmospheric pollutants, aromatic hydrocarbons and heavy metals, on carbon nanomaterials is investigated and the in vivo and in vitro toxicity of nanomaterial-pollutant complexes are studied. Using the dual-isotope-labeling techniques and synchrotron-based X-ray microscopy, the researches about how nanoparticles change or strengthen the biological toxicity of pollutants are carried out to verify the inferred toxicity mechanism of PM2.5. Our results will provide scientific basis for the assessment of the risk of PM2.5 to the environment and human health, as well as new ideas for the comprehensive management of air pollution.

PM2.5浓度增加是导致城市大气污染日益加重的主要原因，环保部已将PM2.5纳入我国常规空气质量评价新标准。但是，PM2.5如何影响人类健康以及详细的毒性作用机制仍不很清楚。本项目从PM2.5小尺寸，大比表面积和高的吸附活性出发，提出了其毒性机制是基于对大气中有害成分的吸附形成复合物，复合物经呼吸系统入肺，然后通过气血屏障入血，从而引起肺部或全身损伤。考虑到PM2.5来源和成分的复杂性，以纳米碳黑，纳米金刚石等作为简化的细颗粒模型，观察碳纳米颗粒对环境中两类重要污染物多环芳烃和重金属的吸附作用，研究纳米颗粒－污染物复合物对细胞和整体动物的生物效应和毒性，重点应用双同位素标记以及同步辐射X射线显微成像技术，开展碳纳米颗粒改变或强化污染物生物学毒性的机理研究，从而验证对PM2.5毒性机制的推断。研究结果将为评估PM2.5对环境和人类健康产生的危害提供科学依据，并为大气污染的综合治理提供新思路。

PM2.5浓度增加是导致城市大气污染日益加重的主要原因，环保部已将PM2.5纳入我国常规空气质量评价新标准。但是，PM2.5如何影响人类健康以及详细的毒性作用机制仍不很清楚。本项目从PM2.5小尺寸，大比表面积和高的吸附活性出发，提出了其毒性机制是基于对大气中有害成分的吸附形成复合物，复合物经呼吸系统入肺，从而导致毒性效应。考虑到PM2.5来源和成分的复杂性，工作中以纳米金刚石和纳米碳黑等碳纳米颗粒作为简化的细颗粒模型，观察碳纳米颗粒对环境中多种重金属的吸附作用，研究纳米颗粒－重金属复合物对细胞和整体动物的生物效应和毒性，从而验证对PM2.5毒性机制的推断。重点应用同步辐射X射线显微成像技术，证明纳米颗粒载带大量金属污染物进入生命体系，导致了呼吸毒性的显著加强。并且，结合多种分子生物学研究方法，揭示了导致呼吸毒性加强的深层次生物学机制－呼吸系统的自噬和溶酶体功能紊乱。研究结果将为评估PM2.5对环境和人类健康产生的危害提供科学依据，并为大气污染的综合治理提供新思路。