Fig. 2

Exposure to stone particles causes sample- and concentration-dependent decreases in cell viability. HBEC3-KT cells (a and d), THP-1 macrophages (b and e), and a co-culture HBEC3-KT cells and THP-1 macrophages (c and f) were exposed to 0–400 μg/mL quartzite, anorthosite, rhomb porphyry, dacite, quartz diorite, hornfels and α-quartz for 24 h. Cell viability was determined by alamarBlue© assay. Results are presented as mean ± SD (n = 4–8). Area under the curve (AUC) values in (d-f) were calculated from the values in (a-c) for the concentration-range of 0–400 μg/mL and are presented related to equal mass (white bars) and surface area (grey bars). All values were normalized to account for differences in baseline prior to calculating AUC values by dividing each value by its respective control. Statistical significance is based on a two-way ANOVA followed by Dunnet’s post-test (a-c) or a one-way ANOVA followed by Tukey post-test (d-f). Based on deviations from normality and homoscedasticity, the data in (b and c) were log-transformed prior to statistical analysis. Asterisks (*) indicate statistically significant difference from the respective control (a-c), while a capped line indicates statistically significant difference between samples (d-f)