Effects of solubility of urban air fine and coarse particles on cytotoxic and inflammatory responses in RAW 264.7 macrophage cell line

• Published in: Toxicology and applied pharmacology 2008-06, Vol.229 (2), p.146-160
• Main Authors: Jalava, Pasi I., Salonen, Raimo O., Pennanen, Arto S., Happo, Mikko S., Penttinen, Piia, Hälinen, Arja I., Sillanpää, Markus, Hillamo, Risto, Hirvonen, Maija-Riitta
• Format: Article
• Language: English
• Subjects: 60 APPLIED LIFE SCIENCES; Air Pollutants - toxicity; Animals; APOPTOSIS; Biological and medical sciences; CELL CYCLE; Cell Line; Cell Survival - drug effects; Chemical constituents; Cytokines - biosynthesis; INFLAMMATION; Inflammation - chemically induced; LIPIDS; LYMPHOKINES; MACROPHAGES; Macrophages - drug effects; Macrophages - metabolism; Medical sciences; MICE; NITRATES; NITRIC OXIDE; Nitric Oxide - biosynthesis; ORGANIC MATTER; ORGANIC SOLVENTS; Particle Size; Particulate matter; Particulate sources; SOILS; Solubility; SULFATES; TOXICITY; Toxicology; Urban air; URBAN AREAS
• ISSN: 0041-008X; 1096-0333
• DOI: 10.1016/j.taap.2008.01.006

We investigated the inflammatory and cytotoxic activities of the water-soluble and -insoluble as well as organic-solvent-soluble and -insoluble fractions of urban air fine (PM 2.5–0.2) and coarse (PM 10–2.5) particulate samples. The samples were collected with a high volume cascade impactor (HVCI) in 7-week sampling campaigns of selected seasons in six European cities. Mouse macrophage cells (RAW 264.7) were exposed to the samples for 24 h. The production of nitric oxide (NO) and proinflammatory cytokines (TNFα, IL-6), and cytotoxicity (MTT-test, apoptosis, cell cycle) were measured. The inflammatory and cytotoxic responses in both size ranges were mostly associated with the insoluble particulate fractions. However, both the water- and organic-solvent-soluble particulate fractions induced TNFα production and apoptosis and had some other cytotoxic effects. Soil-derived water-soluble and -insoluble components of the chemical PM 2.5–0.2 mass closure had consistent positive correlations with the responses, while the correlations were negative with the secondary inorganic anions (NO 3 −, NH 4 +, non-sea-salt SO 4 2−) and particulate organic matter (POM). With the PM 10–2.5 samples, sea salt and soluble soil components correlated positively with the induced toxic responses. In this size range, a possible underestimation of the insoluble, soil-related compounds containing Si and Ca, and biological components of POM, increased uncertainties in the evaluation of associations of the mass closure components with the responses. It is concluded that insoluble components of the complex urban air particulate mixture exert the highest inflammatory and cytotoxic activities in the macrophage cell line but, at the same time, they may operate as carriers for active water- and lipid-soluble components.