Figure 4

The release of inflammatory mediators (sICAM-1, IL-6 and IL-8) is shown after aSNP (Ludox TM-40: light grey, NexSil20: dark grey) incubation on apical/basolateral differentiated cocultures of H441 and ISO-HAS-1, as well as on their appropriate monocultures grown on HTS 24-Transwell^® filters. Cells were exposed to aSNPs from the apical side of the filter membrane to mimic an inhalative exposure to aSNPs. After 4 h serum-free incubation, aSNPs were removed and the cells were cultivated for further 20 h. Subsequently, medium supernatant of both compartments (apical: upper well, basolateral: lower well) was examined. Data are depicted as means ± S.D. of one representative (of three independent) experiments with n = 3 samples for each treatment. All independent experiments showed a comparable reaction following aSNP treatment. Exclusively in coculture, an apical exposure of 6 and 60 μg/ml aSNP caused an increased IL-6 and IL-8 release into the lower well (basolateral/endothelial side). For both monocultures increased amounts of sICAM-1, IL-6 and IL-8 in the lower well were not detected below concentrations of 600 μg/ml aSNP. *P < 0.05, ** P < 0.01 and *** P < 0.001 compared to the untreated control