Release of MCP-1 and IL-8 from lung epithelial cells exposed to volatile organic compounds

Increased indoor air concentrations of volatile organic compounds (VOC) have been shown to contribute to the risk of respiratory and allergic diseases. The aim of this study was to investigate the inflammatory potential of single VOC and mixtures using an in vitro model. TNF-alpha stimulated human lung epithelial cells (A549) were exposed to VOC (1 ng/m3-100g/m3) via gas phase. After 20 h of exposure cytotoxicity and the release of the pro-inflammatory molecules monocyte chemoattractant protein-1 (MCP-1), Interleukin-6 (IL-6) and IL-8 was analysed. Exposure of A549 cells to chlorobenzene, styrene or m-xylene increased the MCP-1 production within the indoor relevant concentration range (1-25,000 microg/m3), higher concentrations increased the secretion of IL-8. Mixtures of aromatic compounds caused comparable effects to the single compounds on MCP-1 and IL-8 with a shift to lower concentration ranges. Neither the aliphatic compounds n-nonane, n-decane, n-undecane, n-dodecane, n-tridecane, and methylcyclopentane nor the mixture of these VOC showed any effects on MCP-1 and IL-8 production. Cytotoxic effects were not observed. These results show that aromatic, but no aliphatic compounds stimulate the release of pro-inflammatory mediators from lung epithelial cells. When aromatic compounds were mixed the sensitivity of lung cells to these compounds was increased.