Figure 7. Acacetin-induced activation of Sirt6 mediates the protection against cardiac senescence by inhibiting protein acetylation. (A) Representative images of SA-β-gal staining for senescent cells in H9C2 cardiac cells transfected with control siRNA or Sirt6 siRNA in the absence or presence of 3 μM acacetin for 72 h. (B) Percentage of senescent cell number in cells treated as in (A). (C) Western blots and relative levels of p53 in cells treated as in (A). (D) Western blots and relative levels of p21 in cells treated as in (A) (n = 4-6, **P < 0.01 vs. D-gal alone, ##P < 0.01 vs. control siRNA with 3 μM acacetin). (E) Western blots and relative levels of H3K9ac in cells treated without (control) or with D-galactose (D-gal, 20 mg/mL) or D-galactose plus acacetin (0.3, 1 or 3 μM) for 72 h (n = 4, **P < 0.01 vs. control, #P < 0.05, ##P < 0.01 vs. with D-galactose alone). (F) Western blots and relative levels of H3K9ac in cells treated as in (A) (n = 4–6, **P < 0.01 vs. D-gal alone, ##P < 0.01 vs. control siRNA with 3 μM acacetin).