The Study Of Cytotoxicity And Its Mechanisms On Lung Cells And Vascular Endothelial Cells Induced By Ambient Particulate Matter

With the rapid development of industrialization and urbanization, air pollutionhas become one of the most important threats to the public health. Associationsbetween exposure to PM and cardiopulmonary diseases are widely demonstrated inepidemiological and toxicological studies. The fine fraction of ambient particles（PM2.5, with aerodynamic diameter of less than2.5μm） might be more detrimental tohuman health than coarser particles （PM2.5-10, with aerodynamic diameter between2.5μm and10μm）. In recent years, the ultrafine particles （with aerodynamic diametersless than100nm） are found to be even more detrimental than PM2.5. A large numberof studies on epidemiological and toxicological data show that the mass concentrationof PM is positively associated with morbidity and mortality of human disease.Exposure to PM can lead to asthma exacerbation, decline of lung function andrespiratory inflammation, and even impair cardiovascular system, nervous system andaccelerate the development of cancer. Till now, the toxicology mechanisms of PM arestill not clear.In present study, coarse (PM_10-2.5), fine (PM_2.5-0.1) and ultrafine (PM_0.1)particulate matters were collected in urban area of Beijing. The total PM_10-2.5, PM_2.5-0.1and PM_0.1were extracted by water ultrasonic method and were dissolved in differentconcentrations. The content of endotoxin in PM was detected by Endotoxin Kit. Inaddition, the total suspended particles （TSP） were collected in the tunnel of Dapu roadin urban area of Shanghai. The organic components were extracted withdichloromethane and were dissolved in different concentrations. Contents of quinoneswere measured by gas chromatography/mass spectrometer （GC-MS） analysis. A549cells and HUVECs cells were used as exposure models in. The toxic effects of particlesize on two cell lines and the effects of endotoxin on cytotoxicity of PM_2.5-0.1wereanalyzed. Furthermore, the toxic effects of organic components and quinones fromtraffic-related particles were analyzed in this study. Cytotoxicity of PMs wasmeasured by MTT assay. The DNA damage was measured by Comet assay. The enzyme activity of lactate dehydrogenase （LDH） in cell culture medium andsuperoxide dismutase （SOD） in cytoplasm were detected by colorimetric assay. Thegeneration of reactive oxygen species was measured by2’,7’-dichloro-fluoresceindiacetate probe.The results showed that:（1） PM_10-2.5, PM_2.5-0.1and PM_0.1had significantcytotoxicity to A549and HUVECs after24h treatment. The cell viabilities weredecreased with the increased concentrations of PMs in a significant does-dependentmanner. The activities of LDH were also increased through a dose-dependent manner.The sensitivity of two cell lines to particles was basically the same. DNA breaks wereobviously increased in the two cell lines with a significant does-dependent manner.The DNA damage caused by PM_2.5-0.1was significantly larger than those of PM_10-2.5and PM_0.1. The level of ROS was increased after exposed to PM_10-2.5, PM_2.5-0.1andPM_0.1through a significant concentration-dependent manner.（2） The organic exactionof traffic-related particles （OE-TRP） also had toxic effects to A549and HUVECsafter treatment for24h. There is no significant difference in the two types of cells.The cell viabilities and the activities of SOD were decreased in a significantdoes-dependent manner, while the activities of LDH were increased. DNA damagewas induced after OE-TRP exposure.（3） The cell viability of A549was decreased in asignificant does-dependent manner after exposure to the three quinones in OE-TRP,including1,4-naphthaquinone （NQ）, anthraquinone （AQ） and benzoquinone （BQ）.The three quinones caused significant DNA damage and ROS generation in cells,through a dose-dependent manner. The potential toxicity of the three quinones wasNQ>AQ>BQ.PM_10-2.5, PM_2.5-0.1and PM_0.1collected in the urban area of Beijing were found tocause significant cytotoxicity in A549and HUVECs cells. Oxidative DNA damagewas also caused by PMs in a significant does-dependent manner. The toxicity ofPM_2.5-0.1is potentially stronger than PM_10-2.5and PM_0.1for A549after high doesexposure. Significant cytotoxicity and genotoxicity were caused by the organiccomponents of traffic-ralated particles collected in Dapu road tunnel in Shanghai. Theairborne quinones play an important role in the toxicity of traffic-related particles. The potential toxicity of the three typical quinones is NQ>AQ>BQ.