Fig. 1.

Effects of mechanical stress (MS) on the expression of Sirtuin 1 (SIRT1) and immune response genes in periodontal ligament (PDL) cells. Cells were cultured with or without MS for up to 48 h (a) and under a MS force of 3–15% (b). mRNA and protein expression levels were examined by reverse transcription–polymerase chain reaction (RT–PCR) and Western blotting, respectively. The data are representative of three independent experiments. The bar graph shows the fold increase in protein or 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.