Fig. 4.

Effect of Sirtuin 1 (SIRT1) siRNA on mechanical stress (MS)-induced immune gene expression in periodontal ligament (PDL) cells. Cells were transfected with control siRNA or SIRT1 siRNA (80 nM), and then exposed to MS (12%) for 24 h. mRNA expression was examined by reverse transcription–polymerase chain reaction (RT–PCR). The data are representative of three independent experiments. The bar graph shows the fold increase in mRNA expression compared to control cells. Columns show mean values of triplicate samples and error bars represent the standard deviation. *Statistically significant differences compared with the control, P < 0·05.