Urban Aerosols Induce Pro-inflammatory Cytokine Production in Macrophages and Cause Airway Inflammation in Vivo

Urban air pollution, especially in developing countries, is a crucial environmental problem. Urban aerosols may contain various kinds of substances and induce harmful effects such as allergic diseases. Therefore, it is critical to clarify the biological effects of urban aerosols on human health. In this study, we evaluated the induction of airway inflammation in vitro and in vivo due to exposure of urban aerosols. We investigated cytokine production and nuclear factor-kappa B (NF-kappa B) activation after stimulation of macrophage cells by exposure of urban aerosols. Urban aerosols were found to induce the production of interleukin (IL)-8, tumor necrosis factor-a and IL-1 beta on macrophage cells. In addition, we showed that NF-kappa B pathway regulated the urban aerosols-induced inflammatory cytokine response. Moreover, the intranasal administration of urban aerosols resulted in increases in the total cell number in bronchoalveolar lavage and infiltration of eosinophils in lung tissue. These results indicate that urban aerosols induce respiratory inflammation and onset of inflammatory disease due to an activation of the immune system.