Buenos Aires Wetland Particulate Matter Wildfire Modifies Rat and Human Immune Cell Function In Vitro

KURTZ MELISA; MASCI, IVANA; DUGOUR, ANDREA; BONETTO JULIÁN; LAMAS. DIEGO; FIGUEROA, JUAN; TASAT DEBORAH

Montevideo

Congreso; SETAC Latin America 15th Biennial Meeting; 2023

Society of Environmental Toxicology and Chemistry (SETAC) Latin America

Natural landscape fires maintain the ecological health of the land, yet adverse health effects associated with exposure to emissions from wildfire (WF) generate public health concerns. Climate change is a key factor in increasing the frequency and severity of WF. Numerous studies found a positive association between exposure to smoke or WF particulate matter (PM) with increased risk of respiratory diseases. Ultrafine WF-PM can penetrate deep into the lungs altering cell function. Herein, we investigated Buenos Aires WF-PM morphochemical characteristics, and evaluated on cultured primary rat alveolar macrophages (rAMs) and human monocytic cells (THP-1) differentiated to macrophages, its cytotoxicity and inflammatory response. WF-PM was characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray powder diffraction (XPD). Rat AMs and THP-1 cells were grown at a density of 125.000 cells/ml in RPMI-1640 medium supplemented with 10% FBS and antibiotics. THP-1 cell were differentiated to macrophages with PMA (10ng/ml) during 24hs. THP-1 and rAMs were exposed for 24h to 10-500 µg/ml WF-PM. Cell metabolism was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) test. Pro-inflammatory cytokines IL-6 and TNFα were determined using specific enzyme-linked immunosorbent assay. SEM and EDX of WF-PM showed a heterogenous morphology, rich in C, O and Si. Low contents of Na, K, Ca, Mg and Cl were also detected. XPD analysis mainly showed the presence of amorphous compounds, possibly SiO2 and carbon. In addition, some low-intensity Bragg peaks were observed, that can be attributed to quartz (SiO2), calcite (CaCO3), halite (NaCl) and sylvite (KCl). We found a high content of Si/dry weight (11.50 ± 0.89 %) possibly due to the large number of burnt grasslands. Both cell types elicited a dose-response decrease (p