Genotoxic and inflammatory effects of organic extracts from traffic-related particulate matter in human lung epithelial A549 cells: the role of quinones.

Traffic-related particulate matter (PM) is associated with adverse health effects. Quinones present in the traffic-related PM are hypothesized to contribute to these harmful effects through reactive oxygen species (ROS) generation. However, the impacts of the traffic-related PM and quinones on inflammatory processes and genotoxic damages are less well known. In present study we aimed to examine the genotoxic and inflammatory impacts of organic extracts from traffic-related PM (oTRP) in human lung epithelial A549 cells, and reveal the contributions from quinones. Significant cytotoxicity and DNA damage were caused by oTRP. The pro-inflammatory genes, interleukin-6 (Il-6), interleukin-8 (Il-8) and tumor necrosis factor (Tnf), and two aromatic hydrocarbon receptor-regulated genes, Cyp1a1 and 1b1, were significantly up-regulated by oTRP. A concomitant increase in ROS was observed, suggesting that oTRP may mediate genotoxic and inflammatory effects through oxidative stress pathway. Second, the effects from two typical airborne quinones, 9,10-anthraquinone (AQ) and 1,4-naphthroquinone (NQ) were compared. NQ, but not AQ, induced significant DNA damage in A549 cells. NQ up-regulated Il-8, Tnf, and Mcp-1 genes, while AQ induced the expression of Rantes gene. These results suggest that the NQ and AQ may participate in the pro-inflammatory responses through releasing different types of cytokines/chemokines.