CONTRIBUTION OF ENDOTOXIN IN MACROPHAGE CYTOKINE RESPONSE TO AMBIENT PARTICLES IN VITRO

Abstract

Ambient particles may cause pulmonary inflammation with ensuing morbidity. Particle-induced production of proinflammatory cytokines in vitro has been used as an indicator of particle toxicity. To identify particle components that were related to particle toxicity, Andersen dichotomous impactors were used to collect ambient fine (PM 2.5 ) and coarse (PM 2.5-10 ) particles in central Taiwan with extraction in endotoxin-free water. Mouse mono-cyte-macrophage cell line RAW 264.7 cells were exposed to particle extracts at 40 g/ml for 16 h, and tumor necrosis factor-alpha (TNF- f ) was measured in the medium by enzyme-linked immunosorbent assay (ELISA). Cell viabilities were all greater than 82%. Coarse particles stimulated higher TNF- f production than fine particles, and this was associated with greater particulate endotoxin content. Polymyxin B inhibited 42% of TNF- f production elicited by coarse particles and 32% of TNF- f production elicited by fine particles. In fine particles, TNF- f production was negatively correlated with Zn content, while no element in coarse particles correlated with TNF- f production. Results suggest that endotoxin and other components may be important factors for TNF- f production by macrophages in vitro.