Nuclear factor-kappa B is not involved in titanium dioxide-induced inflammation

Research over recent years have shown that titanium dioxide (TiO2) nanoparticles (NPs) induce inflammation in various lung, kidney, liver and brain cells. Although the mechanism of inflammation is unclear, existing literature suggests the underlying role of oxidative stress. On the other hand, it has also been shown that nuclear factor-kappa B (NF-kappaB) is activated in response to pro-inflammatory cytokines. In this study we investigated the involvement of NF-kappaB in TiO2-induced inflammation in human lung adenocarcinomic epithelial cells (A549 cells). After 24h of treatment, IL-8 protein release from A549 cells, induced by 10, 50 and 250 microg/ml of P25 TiO2 NPs, were statistically significantly raised, compared to that of the control. This finding corroborates existing literature in that TiO2 NPs induce a dose-dependent increase in the release of IL-8 protein when exposed to A549 cells. However, the binding of NF-kappaB DNA was not affected after 6 h of incubation with P25. Therefore, NF-kappaB DNA binding is not the likely transcription pathway that leads to TiO2-induced inflammation.