Effects of Different Components of PM(2.5) on the Expression Levels of NF-κB Family Gene mRNA and Inflammatory Molecules in Human Macrophage

Background: Studies have found that exposure to fine particulate matter with sizes below 2.5 µm (PM(2.5)) might cause inflammation response via the NF-κB pathway. To date, only a few studies have focused on the toxicity of different components of PM(2.5). We aimed to explore the effects of PM(2.5) with different components on the expression levels of NF-κB family gene mRNA and inflammatory molecules in human macrophages. Methods: Human monocytic cell line THP-1-derived macrophages were exposed to water-soluble (W-PM(2.5)), fat-soluble (F-PM(2.5)), and insoluble (I-PM(2.5)) PM(2.5). The cell survival rate was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The levels of inflammatory molecules were determined by enzyme-linked immunosorbent assay (ELISA), and the relative mRNA levels of the NF-κB family gene were determined by real time PCR. Results: PM(2.5) could decrease the cell viability. After exposure to W-PM(2.5), the levels of interleukins (IL)-1β and IL-12 p70 significantly increased. After exposure to F-PM(2.5), the levels of IL-12 p70 significantly increased. The levels of IL-12 p70 and TNF-α after exposure to I-PM(2.5) were significantly higher than that in W- and F-PM(2.5) treatment groups. The levels of IL-8, C reactive protein (CRP), and cyclooxygenase (COX)-2 increased only after exposure to I-PM(2.5). F-PM(2.5) increased the mRNA levels of NF-κB genes, especially NF-κB(1) and RelA. Conclusions: PM(2.5) can decrease the cell survival rate and up-regulate the expression of NF-κB family gene mRNA and inflammatory molecules. The main toxic components of PM(2.5) related to inflammatory response in macrophages were the I-PM(2.5).