Met activates p53, p-p53, IFI16 and p-AMPK in HASMCs (passage 3). HASMCs were treated with Met at various concentrations (0, 2, 5 and 10 mmol/l) for 24 h. (A) mRNA expression levels of p53 and IFI16 were measured by reverse transcription-quantitative polymerase chain reaction. Histogram represents the fold change in p53 and IFI16 mRNA expression normalized to GAPDH relative to the control (met 0 mM). (B) Western blotting was performed to detect p53, p-p53, IFI16, AMPK and p-AMPK protein expression. GAPDH was used as a loading control. (C) Histogram represents the fold change in p53, p-p53, IFI16, AMPK and p-AMPK protein expression normalized to GAPDH relative to the control (met 0 mM). All data are presented as the means ± standard deviation of three independent experiments. *P<0.05, **P<0.01 and ***P<0.001 vs. the control group. AMPK, 5′ adenosine monophosphate-activated protein kinase; HASMCs, human aortic smooth muscle cells; IFI16, interferon-inducible protein 16; Met, metformin; p-, phosphorylated.