Validation of microarray data by qPCR analysis.

Five of regulated genes were representatively selected for validation of their expression levels by qPCR, in comparison to the microarray. These were namely COX-2, LCN2, OPG, RANKL and SAA3. The values represent fold-changes of gene expression levels in response to P. gingivalis, in relation to control, by microarray analysis (A), or by qPCR analysis (B). The minus values (also in bold letters) indicate down-regulation. When a fold-change value is missing in one of the two time-points, the regulation of gene expression at that time-point was less that 2-fold. *p<0.05, **p<0.01, ***p<0.001.