EICOSAPENTAENOIC ACID EXHERTS A PROTECTIVE EFFECT ON PALMITATE INDUCED APOPTOSIS OF H9c2 CARDIOMYOBLASTS

Introduction. Intracellular accumulation of fatty acid metabolites in nonadipose tissues has been proposed to play an important role in the pathogenesis of diabetes mellitus. Moreover, lipotoxicity may contribute to cell death and cardiac dysfunction. Evidence is emerging that saturated fatty acids induce cell death through apoptosis and this effect is specific for palmitate and stearate. n-3 polyunsaturated fatty acids (PUFAs) have been implicated in the protection against cardiovascular diseases, cardiac ischemic damage and myocardial dysfunction. In the present study we showed that supplementation with the n-3 PUFAs eicosapentaenoic acid (EPA), to culture medium of H9c2 rat cardiomyoblasts protects cell against palmitate-induced apoptosis. Methods: Experiments were performed by using H9c2 rat ventricular cardiomyoblasts. Apoptosis was detected by trypan blue exclusion, MTT or caspase activity assays. Gene expression was investigated by Real Time PCR. Signal transduction pathways was investigated by western blotting. Results: Our results indicate that palmitate induces apoptosis in a dose dependent manner. In particular at 500 M dose it increased caspase activity by about 4 fold after 24 h of treatment. The incubation with 60 M EPA inhibited palmitate-induced apoptosis of H9c2. Preliminary results indicate that the anti-apoptotic effect of EPA could be mediated by the modulation of the transcriptional peroxisome proliferator–activated receptor  coactivator-1 considered a master regulator of myocardial energy metabolism in diverse pathophysiological conditions, as well as activation of SIRT1. Interestlingy, the protective effect of EPA on cell viability seems also involve the rapamycin-insensitive companion of mammalian target of rapamycin (mTOR) (Rictor) a key member of mTOR complex-2 that promotes cellular survival.