Conclusions
These findings suggest that PM&sub2;.₅ exposure induces the inflammatory responses from both macrophages and neutrophils involvement.
Results
C57BL/6 mice were exposed to PM&sub2;.₅ or filtered air (6 hours/day, 5 days/week) for 5, 14, and 21 days, respectively, in Columbus, OH. At the end of each of the exposure periods, we investigated the inflammatory response through flow cytometry, histology, intravital microscopy, and real-time PCR. PM&sub2;.₅-exposed mice demonstrated a significant inflammatory response after 5 days of exposure. In the lung tissue and bronchoalveolar lavage fluid, monocytes/macrophages showed a transient response, while neutrophils showed a cumulative response. In addition, exposure to PM&sub2;.₅ resulted in elevation of the monocyte chemoattractant protein 1 (MCP-1) cytokine, a monocyte/macrophage attractant in blood, at an early stage of exposure. Conclusions: These findings suggest that PM&sub2;.₅ exposure induces the inflammatory responses from both macrophages and neutrophils involvement.