Fig. 1

TiO₂ NPs induced the expression of sLe^x and PSGL-1. U937 cells were exposed to TNFα (10 ng/mL) or to concentration of 0.001, 0.003, 0.01, 0.03, 0.3, 1, 3, 10, 30 and 100 μg/mL of TiO₂ NPs of 50 nm during 3 h. Unexposed cultures were used as negative controls. a Histograms of the sLe^x expression obtained by flow cytometry. The continuous line represents control unexposed cells and the dotted line corresponds to the different treatments. b Histograms of the PSGL-1 expression obtained by flow cytometry. The continuous line represents control unexposed cells and the dotted line corresponds to the different treatments. c and d Normalization of the results presented as as a percentage of expression (fluorescencence intensity with respect to control) as mean ± SD of three separate experiments. After 3 h of exposure to TiO₂ NPs an expression of sLe^x and PSGL-1 was as strong as the induced by TNFα. *p < 0.05 vs negative control