Figure 6.

Gene expression and protein release of monocyte chemotactic protein (MCP-) 1 (a,b) and Interleukin (IL-) 8 (c,d) following exposure to metal salts. Gene expression (a,c) and protein release into cell culture supernatants (b,d) were determined for THP-1 monocytes and macrophages after 48 h of treatment with the concentration of 100 µM of cobalt, chromium and nickel salts. Untreated cells served as negative controls. Data (n = 3) are depicted as single datapoints with mean ± SD. Gene expression data are shown as percentage of untreated cells (2^{(−∆∆Ct)}, 100%, dotted line) while protein release data represent values of the specific protein amount normalized to total protein content in cell culture supernatants. Significances between groups were calculated with two-way ANOVA and Bonferroni’s multiple comparison test as post hoc test using ∆CT values for gene expression and specific protein amount normalized to total protein content for protein release in cell culture supernatants. Significantly different between stimulation groups: * p < 0.05, ** p < 0.01, *** p < 0.001; significantly different from untreated control: # p < 0.05, ## p < 0.01, ### p < 0.001. Abbreviations: n.d. = not detectable; NC = negative control (untreated cells).