Fig. 6

Levels of pro-inflammatory mediators IL-1β, IL-6, IL-8 and TNF-α in culture medium of cells exposed in submerged conditions in inserts. Co-cultures (A549 + THP-1) were exposed in inserts for 3 h to suspensions of TiO₂ (NM105, NM101, NM100) and CeO₂ (NM212), to achieve deposited doses of around 1, 3 and 10 μg/cm². Suspensions were then replaced by fresh medium and cells were kept for 21 h at the incubator with NMs deposited on their surface. At 24 h, IL-1β, IL-6, IL-8 and TNF-α levels were measured by ELISA multiplex in cell culture medium (apical and basal sides). A specific control (cells exposed to culture medium) and positive control (LPS 20 μg/mL) (not shown on the graph) were used for each NM used. Data represent the mean ± Standard Deviation (SD) of three independent experiments. A Kruskal-Wallis test followed by Dunn’s post-hoc test were performed to compare treated groups to controls (*p < 0.05; **p < 0.01; ***p < 0.001)