Inflammatory Response of Monocytes to Ambient Particles Varies by Highway Proximity

Epidemiological studies have demonstrated associations of chronic respiratory disease with near-roadway pollutant exposure, effects which were independent of those of regional air pollutants. However, there has been limited study of the potential mechanisms for near-roadway effects. We examined the in vitro effect of respirable particulate matter (PM) collected adjacent to a major Los Angeles freeway and at an urban background location. PM was collected on filters during two consecutive fifteen day periods. Oxidative stress and inflammatory response to PM aqueous extract was assessed in THP-1 cells, a model for evaluating monocyte lineage cell responses. The near-roadway PM induced statistically significantly higher levels of IL-6, IL-8 and TNFa (P<0.01) but not of IL-1s (P=0.06) or of intracellular reactive oxygen species (P=0.17). PM-induced pro-inflammatory protein expression was attenuated by antioxidant pre-treatment, and PM stimulation enhanced activity of protein kinases including extracellular sig...