US EPA

2333423 

Journal Article 

Inflammatory response to fine particulate air pollution exposure: Neutrophil versus monocyte 

Xu, X; Jiang, SY; Wang, T; Bai, Y; Zhong, M; Wang, A; Lippmann, M; Chen, L; Rajagopalan, S; Sun, Q 

2013 

1 

PLoS ONE
EISSN: 1932-6203 

8 

8 

e71414 

English 

23951156 

10.1371/journal.pone.0071414 

WOS:000323124000056 

OBJECTIVES: Studies have shown that chronic exposure to ambient fine particulate matter (less than 2.5 µm in aerodynamic diameter, PM₂.₅) pollution induces insulin resistance through alterations in inflammatory pathways. It is critical to study how the immune system responds to this stimulant, which has been linked to cardiovascular and autoimmune diseases, but few studies have been focused on such involvement of both neutrophils and monocytes in a timely manner. We hypothesized that the neutrophil was involved in the inflammatory response to air pollution.

METHODS AND RESULTS: C57BL/6 mice were exposed to PM₂.₅ 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. PM₂.₅-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 PM₂.₅ 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 PM₂.₅ exposure induces the inflammatory responses from both macrophages and neutrophils involvement.