SIRT3 and cardiac hypertrophy: Western blot data (Figure 6D) showed that myocardial AMPK phosphorylation level and the expressions of SIRT3 were markedly downregulated by ATO exposure, however, Honokiol pretreatment significantly reversed these decreases, indicating that Honokiol exerted‐protection of cardiac hypertrophy during ATO‐induced cardiotoxicity is mediated through activating the Sirt3/AMPK signaling pathway.