Effect of exposure conditions on SWCNT-induced inflammatory response in human alveolar epithelial cells

► IL-8 expression was enhanced in the presence of serum. ► SWCNT-induced IL-8 expression kept increasing, even after removal of SWCNTs. ► SWCNT exposure under dynamic environment induced changes in IL-8 expression. There has been an increasing interest in the development and applications of carbon nanotubes (CNTs) due to their huge potential in industrial and medical applications, but the toxicological properties of these materials have not been well characterized, especially the effects of nanoparticle exposure under different conditions on cellular responses. Nano-structured particles are potentially hazardous when they deposit in the respiratory system. In this study, we characterized the effects of single walled CNT (SWCNT) exposure on interleukin-8 (IL-8) expression in human alveolar epithelial cells (A549) under various exposure conditions. We measured the level of IL-8 expression in the presence and absence of serum following exposure of SWCNTs. The results demonstrated that IL-8 expression was enhanced in the presence of serum. When A549 cells were exposed to low concentrations of SWCNTs, IL-8 expression kept increasing, even after removal of SWCNTs from the media. In addition, SWCNT exposure under dynamic cell growth condition induced changes in IL-8 expression.