The Effects of Particulate Matter on C57BL/6 Peritoneal and Alveolar Macrophages

The presence of ambient particulate matter (PM) poses more dangers to human health than that of other common air pollutants such as Carbon dioxide (Co2) and ozone.  Epidemiologic studies show a direct correlation between PM and the risk of respiratory and cardiovascular diseases. The immune system seems to play a critical role in the process of these diseases. The main goal of this study was to investigate the effect of Tehran particulate matter in two aerodynamic diameters (PM2.5 and PM10) on alveolar macrophages (AM) from C57/BL6 mice. To evaluate the inflammatory effects of PMs, cultured alveolar, and peritoneal macrophages were treated with PM2.5 and PM10 (concentrations of 5 µg/mL and 10 µg/mL). Tumor necrosis factor-alpha (TNF-α) and IL-10 (representatives of inflammatory and anti-inflammatory cytokines, respectively) were assessed in the culture supernatant by ELISA. Expression of arginase and inducible nitric oxide synthase (iNOS) genes was carried out by quantitative real-time PCR. Different functional types of cultured alveolar macrophages (M1, M2) were also determined in this study. Our results suggest that PM2.5 induces M1 inflammatory phenotype in comparison with PM10. We found Also, an increase in TNF-α and M1-related gene expression (iNOS), as well as a decrease in both IL-10 and M2 phenotype genes (Arginase). Moreover, a reduction in phagocytic capacity and increased apoptosis function of macrophage cells were detected. PM2.5 as a major component in hydrocarbons has a considerable effect on polarizing the alveolar macrophages to an inflammatory phenotype and eliciting lung inflammation in mice.