Fig. 3

a, b Histograms representing the high content imaging data for a MSC and b Beas2B cells exposed to Au or SiO₂ NPs at 150 µg/ml for 24 h (subcytotoxic conditions) in the absence or presence of 5 mM NAC, a free radical scavenger. The results for ROS, mitochondrial health and autophagy are presented relative to the level observed for untreated control cells. c Histograms representing the lysosomal activity of MSC and Beas2B exposed to Au or SiO₂ NPs (150 µg/ml for 24 h) at 1 days after NP exposure. Data are expressed relative to the level for untreated control cells (100%). d Histograms representing the cellular proliferation of MSC and Beas2B exposed to Au or SiO₂ NPs (150 µg/ml for 24 h) at 3 and 6 days post NP exposure. Data are expressed relative to the level for untreated control cells (100%). a–d Data are expressed as mean ± SD (n = 3). The degree of statistical significance is indicated when relevant (*p < 0.05; **p < 0.01; ***p < 0.001)