A, Senescence was evaluated through the senescence-associated β-galactosidase (SA-β-gal) staining of saline or Ang Il–treated wild-type (WT) and SIRT1-VSMC–specific knockout (SV-KO) VSMCs infected with Ad-U6 (a control RNAi vector) or Ad-p21 RNAi (vectors for adenovirus-mediated knockdown of p21) for 24 h. Blue-stained cells were considered senescent. The bar represents 150 μm. B, Statistical analysis of the percentage of sA-β-gal–positive cells. Five random fields of view were analyzed for 1 group (n=7–10). C, Relative MCP-1/CCL2 mRNA expression level detected by real-time polymerase chain reaction in saline or Ang Il–treated WT and SV-KO VSMCs infected with Ad-U6 or Ad-p21 RNAi. D–F, Relative binding level of RelA/p65 to input on indicated region of human MCP-1/CCL2 promoter. *P<0.05, **P<0.01, ***P<0.001.