Environmental Fine Particulate Matter (PM 2.5) Activates the RAW 264.7 Macrophage Cell Line even at Very Low Concentrations as Revealed by 1H NMR

Because of the association between inhalation of airborne particulate matter (PM) and human respiratory and cardiovascular disease, it is necessary to understand the tissue damage induced by these particles. One of the cell types principally involved in the body's reaction to PM are macrophages, which remove particles in the airway passages and the lungs through phagocytosis. In fact, when macrophages are exposed to a toxic agent such as PM, they undergo a series of changes (including variations in morphology, an increase in glycolysis, and consequent lactate production and the release of cytokines such as interleukin-6 and tumor necrosis factor-α) necessary to transform them from "resting" to "activated" macrophages. Because ¹H NMR is extremely useful in monitoring, noninvasively, macrophage metabolism and because this technique has never been utilized to examine macrophage activation after exposure to PM, it was the purpose of the present study to investigate the effects of PM exposure on the RAW 264.7 stabilized macrophage cell line using ¹H NMR spectroscopy. PM with a diameter 1H NMR spectroscopy is an extremely sensitive probe in observing subtle variations in macrophages after exposure to PM 2.5.