Cardioprotective Effects of Simvastatin in Doxorubicin-Induced Acute Cardiomyocyte Injury

Oxidative stress and mitochondrial dysfunction play a key role in the early stage of Doxorubicin (Doxo)-induced cardiotoxicity. Our study investigated the potential cardioprotective role of Simvastatin (Sim), widely known for its antioxidant properties, in an in vitro model of Doxo-induced acute cardiotoxicity. Human Cardiomyocytes (HCMs) were treated with Sim (10 mu M, 4 h) and then co-exposed to Doxo (1 mu M) and Sim for 20 h. Our data showed that Sim co-treatment significantly (p < 0.05) reduced both cytosolic and mitochondrial Doxo-induced reactive oxygen species overproduction. In Sim co-treated cells, significant reductions in nuclear factor erythroid 2-related factor 2 (Nrf2) gene expression (p < 0.01) and catalase (CAT), heme-oxygenase 1 (HO-1), and superoxide dismutase 2 (SOD2) levels (p < 0.05) compared to Doxo-treated cells were also demonstrated, suggesting a decreased need for compensatory antioxidant defense responses. Moreover, significant reductions in Doxo-induced mitochondrial calcium overload, mitochondrial membrane depolarization (p < 0.005), and apoptosis (p < 0.005) confirmed the protective effects of Sim co-treatment on cardiomyocytes. These data confirm that Sim could be a valuable therapeutic strategy for reducing Doxo-induced HCM damage, preventing the development of dilated cardiomyopathy and long-term heart damage, which are the main limitations of anthracycline use. Finally, real-time PCR analysis revealed that Sim co-treatment significantly reduced (p < 0.001) the Doxo-induced overexpression of MAP4K4, a mitogen-activated protein kinase kinase kinase kinase-4 (MAP4K4) involved in oxidative stress-induced cell death, thus suggesting the involvement of other molecular mechanisms in Sim-mediated cardioprotection.