北京市PM2.5中类腐殖质的生物氧化应激效应初探

为研究细颗粒物(PM_2.5)中类腐殖质(humic-like substances, HULIS)的生物氧化应激效应，对北京市区和郊区不同季节大气PM_2.5及其中碳质组分和金属元素浓度进行测定，并以大鼠肺泡巨噬细胞(NR8383)作为细胞模型，分析PM_2.5及其重要组分诱导产生内源性ROS的能力，研究了PM_2.5中HULIS对诱导产生内源性ROS的贡献. 结果表明:①冬季PM_2.5中碳质组分浓度及内源性ROS浓度(单位为μg zymosan/m3，以酵母聚糖(zymosan)表征的单位体积空气中内源性ROS的浓度)明显高于夏季，但夏季PM_2.5具有更高的生物氧化潜力(单位为μg zymosan/mg PM，以酵母聚糖(zymosan)表征的单位质量颗粒物的生物氧化潜力). ②PM_2.5中碳质组分和一些金属元素浓度均与PM_2.5生成的内源性ROS浓度之间具有较高的相关性. ③HULIS单独诱导生成的内源性ROS浓度也呈冬季〔市区和郊区分别为(55.46±22.69) (43.27±23.89) μg zymosan/m3〕高于夏季〔市区和郊区分别为(18.73±11.94) (7.88±3.63) μg zymosan/m3〕的特征. 在北京市区和郊区两个采样点，由HULIS单独诱导生成的内源性ROS浓度与PM_2.5诱导生成的总内源性ROS浓度之间具有较好的相关性. 研究显示，HULIS是PM_2.5中诱导ROS生成的关键组分，在北京市区和郊区两个采样点HULIS对PM_2.5诱导的内源性ROS的贡献率分别为42%和37%. 

Preliminary Study on Biological Oxidative Stress Effects of Humic-Like Substances in PM2.5 in Beijing

In order to study the biological oxidative stress effect of humic-like substances (HULIS) in fine particulate matter (PM_2.5), the concentrations of carbonaceous components and metal elements in atmospheric PM_2.5 in the urban and suburb areas of Beijing were measured. Rat alveolar macrophages (NR8383) were used as cell model to determinate the ability of PM_2.5 and its important components to induce endogenous ROS and the contribution of HULIS in PM_2.5 to the induction of endogenous ROS. The results showed that: (1) The concentrations of carbonaceous components and endogenous ROS (the unit is μg zymosan/m3, representing the concentration of endogenous ROS per unit volume of air) in PM_2.5 in winter were significantly higher than those in summer, but PM_2.5 in summer had higher biological oxidative potential (the unit is μg zymosan/mg PM, representing the biooxidative potential of the unit mass of particulate matter). (2) The concentrations of carbonaceous components and some metal elements in PM_2.5 all had high correlation with the concentration of endogenous ROS induced by fine particulate matter. (3) The endogenous ROS induced by HULIS alone was also higher in winter ((55.46±22.69) (43.27±23.89) μg zymosan/m3 in urban and suburbs, respectively) than in summer ((18.73±11.94) (7.88±3.63) μg zymosan/m3 in urban and suburbs, respectively). There was also a good correlation between the endogenous ROS concentration induced by HULIS alone and the total endogenous ROS concentration induced by PM_2.5 at the two sampling sites in the urban and suburban areas of Beijing. The results showed that HULIS was a key component that induced ROS generation in PM_2.5 at the two sampling sites in the urban and suburban areas of Beijing, and the contribution rates of HULIS to PM_2.5-induced endogenous ROS were 42% and 37%, respectively.