OXIDATIVE AND INFLAMMATORY RESPONSE OF RAW 264.7 MURINE MACROPHAGES EXPOSED TO AIR POLLUTION PARTICULATE MATTER

CÁCERES L; PAZ M; GARCÉS M; OJEDA D; TASAT D; GONZALEZ MAGLIO D; MARCHINI T; EVELSON PA

Mar del Plata

Congreso; LXI REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INVESTIGACIÓN CLÍNICA (SAIC); 2016

Theexposure to environmental particulate matter (PM) is associated withincreased cardiorespiratory morbidity and mortality rates. Alveolar macrophagesare suggested to play a central role in this scenario, triggering bothinflammation and oxidative stress following PM inhalation. However, the pathways linkingthese responses remain uncertain. In order to address such mechanisms, westudied the murine macrophage cell line RAW 264.7 after an exposure todifferent PM samples, Residual Oil Fly Ash (ROFA) andConcentrated Ambient Particles (CAPs), at 0, 50, 100, and 200 µg/mL for 24 h. Intracellular redox status was assessed bydichlorofluorescein fluorescence, which was increased in a dose-dependentmanner by up to 73% and 71% at 200 µg/mL of ROFA and CAPs, respectively(control: 16±5 x 103) AU, P<0.05). Oxidativedamage to lipids was evaluated as thiobarbituric acidreactive substances (TBARS) by a fluorometric assay, finding a dose-dependentincrease by up to 356% and 144% at 200 µg/mL of ROFAand CAPs, respectively (control: 0.29±0.03 mmol TBARS/mg protein, p<0.01).Nitric oxide production was indirectly determined as nitrite content incell culture supernatants by the Griess assay, finding a dose-dependent increase by up to 37% at 200µg/mL of ROFA (control: 3.9±0.3 nmol NO2-/mgprotein, p<0.01), while no significant differences were observed afterCAPs incubation. Moreover, cell culture supernatants fromboth ROFA- and CAPs-exposedcells showed increased levels of TNF-α and IL-6. Given that ROFA and CAPs differ inelemental composition, PM chemistry might be determinant for the reported effects.These findings suggest that alveolar macrophages are in part responsible forthe oxidative and inflammatory response observed after the exposure toenvironmental PM, and therefore contribute to the understanding of the cellularpathways triggered byPM inhalation.