Abstract: AIM To investigate the effect and the molecular mechanisms of EPA on apoptosis in palimitate-induced myocardial cells. METHODSA palmitate-induced mouse myocardial cell model was utilized. Groups were randomly divided into a blank control group, a PAL-stimulated group, an EPA+PAL stimulated group, and an EPA+PAL+Compound C group. Cell viability ratio was determined by MTT and apoptosis was assessed by TUNEL assay. Western blot method was utilized to detect the expression of cleaved caspase 3, Drp1 and p-AMPK. RESULTSWhen myocytes were exposed to palmitate (400μmol/L) for 24 h, the myocytes showed decrease of cell viability (P<0.05), increase in number of TUNEL-positive cells (P<0.05), and activation of cleaved caspase 3, as compared with control (P<0.05). Additionally, PAL-induced apoptosis decreased phosphorylation of AMPK (P<0.05) and up-regulated the protein level of Drp1 (P<0.05). Further, co-incubation of the cell with EPA (50 μmol/L) and PAL suppressed PAL-induced apoptosis by activated phosphorylation of AMPK and inhibited expression of Drp1 (P<0.05). Compound C, an AMPK antagonist, attenuated the protective effects of EPA against PAL-induced apoptosis though suppression of AMPK phosphorylation (P<0.05) which subsequently activated expression of Drp1 and cleaved caspase 3 (P<0.05). CONCLUSIONEPA inhibits PAL-induced apoptosis in neonatal mouse cardiomyoctes via activation of the AMPK pathway and suppression of Drp1 expression. These results provide new insights for myocardial protective effects of EPA.