Fig. 5

Stone particles induce sample- and concentration-dependent increases of pro-inflammatory cytokines in a HBEC3-KT/THP-1 co-culture. Co-cultures of HBEC3-KT cells and THP-1 macrophages were exposed to 0–400 μg/mL quartzite, anorthosite, rhomb porphyry, dacite, quartz diorite, hornfels and α-quartz for 24 h. The release of CXCL8 (a and e), IL-1β (b and f), IL-1α (c and g) and TNFα (d and h) in the cell culture supernatant was measured by ELISA. Results are presented as mean ± SD (n = 4). Area under the curve (AUC) values in (e-h) were calculated from the values in (a-d) for the concentration-range of 0–200 μg/mL, and are presented related to equal mass (white bars) and surface area (grey bars). Statistical significance is based on a two-way ANOVA followed by Dunnet’s post-test (a-d) or a one-way ANOVA followed by Tukey post-test (e-h). Values in (a-d) were log-transformed prior to statistical analysis based on deviation from normality and homoscedasticity. Asterisks (*) indicate statistically significant difference from the respective control (a-d), while a capped line indicates statistically significant difference between samples (e-h)