Search

Long and short-term exposure to atmospheric particulate matter (PM) has detrimental effects on human health. The effective mechanisms leading to PM toxicity are still not fully understood, even if it is known that physical-chemical properties, strongly influenced by sources and atmospheric processes, are known to play an important role. In this work, PM10 samples were collected, at an urban background site in southern Italy, to determine cytotoxicity (using MTT test on A549 cells), genotoxicity (using the comet assay), and intracellular oxidative stress on A549 cells exposed for 24 h to aqueous extracts of PM10 samples. Organic carbon (OC) and elemental carbon (EC) content of PM10 and acellular determination of oxidative potential with DTT assay were performed to compare results of acellular and cellular biological assays. Cellular (OSGCV and MTTV) and acellular (OPDTTV) outcomes, normalized in volume, are well correlated (statistically significant results) with carbon content suggesting that combustion sources play an important role in determining cellular oxidative stress and cytotoxicity of PM10. Even if the number of data is limited, genotoxicity results are well correlated (Pearson r > 0.95) with OSGCV and MTTV, and a weaker, but statistically significant correlation was observed with OPDTTV. OSGCV is well correlated with the cell mortality observed with the MTTV test and a lower, but still statistically significant correlation is observed between MTTV and OPDDTV. A statistically significant correlation was found between OPDTTV and OSGCV results. When the outcomes of the cellular and acellular assay are compared normalized in mass (i.e., intrinsic values), the correlations become significantly weaker suggesting that the different sources acting on the site produces particulate matter with different toxicological potential influencing differently the biological tests studied. [ABSTRACT FROM AUTHOR]

Atmospheric particulate matter (PM) is one of the major risks for global health. The exact mechanisms of toxicity are still not completely understood leading to contrasting results when different toxicity metrics are compared. In this work, PM 10 was collected at three sites for the determination of acellular oxidative potential (OP), intracellular oxidative stress (OSGC), cytotoxicity (MTT assay), and genotoxicity (Comet assay). The in vitro tests were done on the A549 cell line. The objective was to investigate the correlations among acellular and intracellular toxicity indicators, the variability among the sites, and how these correlations were influenced by the main sources by using PMF receptor model coupled with MLR. The OPDTT V , OSGC V , and cytotoxicity were strongly influenced by combustion sources. Advection of African dust led to lower-than-average intrinsic toxicity indicators. OPDTT V and OSGC V showed site-dependent correlations suggesting that acellular OP may not be fully representative of the intracellular oxidative stress at all sites and conditions. Cytotoxicity correlated with both OPDTT V and OSGC V at two sites out of three and the strength of the correlation was larger with OSGC V. Genotoxicity was correlated with cytotoxicity at all sites and correlated with both, OPDTT V and OSGC V , at two sites out of three. Results suggest that several toxicity indicators are useful to gain a global picture of the potential health effects of PM. [Display omitted] • Acellular and intracellular oxidative stress indicators are strongly influenced by combustion sources. • Lower-than-average intrinsic toxicity was observed during the advection of African dust. • Acellular OPDTT may not fully represent the intracellular oxidative stress at all sites and conditions. • Cytotoxicity correlated with both the OPDTT V and the OSGC V at two sites out of three. • Genotoxicity obtained via the Comet assay was well correlated with cytotoxicity at all sites. [ABSTRACT FROM AUTHOR]