Abstract: Objective To investigate whether resveratrol alleviates hyperglycemia-induced cardiomyocyte hypertrophy by enhancing the expression of silent information regulation 2 homolog 1 (SIRT1) to maintain mitochondrial homeostasis. Methods Rat cardiomyocytes H9c2 cells with or without lentivirus-mediated mRNA interference of SIRT1 were cultured in high glucose (HG) and treated with resveratrol for 72 h. The changes in superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, reactive oxygen species (ROS) level, and relative surface of the cells were examined, and the mRNA expressions of atrial natriuretic factor (ANF) and brain natriuretic peptide (BNP) and protein expressions of SIRT1, mitochondrial fusion related proteins optic atrophy protein 1 (OPA1) and mitofusin 2, mitochondrial division related protein dynamin-related protein 1 (DRP1) and fission protein 1 (FIS1), and mitophagy-related proteins BNIP3L and LC3 were detected using RT-qPCR and Western blotting. Results HG exposure significantly decreased SOD activity, increased MDA content, ROS production, relative cell surface, and the mRNA expressions of ANF and BNP in the cardiomyocytes; the protein expressions of SIRT1, OPA1, mitofusin 2 and BNIP3L and LC3-II/LC3-I ratio were all decreased and the protein expressions of DRP1 and FIS1 increased in HG-exposed cells (P<0.01). All these changes in HG-exposed cardiomyocytes were significantly alleviated by treatment with resveratrol (P<0.05). The protective effects of resveratrol against HG exposure in the cardiomyocytes were obviously attenuated by transfection of the cells with si-SIRT1 (P<0.05). Conclusion Resveratrol inhibits hyperglycemia-induced cardiomyocyte hypertrophy by reducing oxidative stress, the mechanisms of which involve enhancement of SIRT1 protein expression, regulation of mitochondrial fusion and division balance, and promoting BNIP3L-mediated mitophagy to maintain mitochondrial homeostasis in the cells.

Key words: diabetic cardiomyopathy; cardiac hypertrophy; resveratrol; mitochondrial; oxidative stress; SIRT1