['Myocardial hypoxia-reoxygenation (H-R) is associated with upregulation of metalloproteinases (MMPs). Upregulation of MMPs is associated with cell injury. Previous studies have shown that fish oil can protect myocardium from injury induced by H-R. This study was designed to examine the effect of eicosapentanoic acid (EPA), one of the major components in fish oil, on the modulation of MMP-1 expression in response to H-R in cultured adult rat myocytes.', 'Myocytes isolated from adult Sprague-Dawley rat hearts were cultured with or without EPA or arachidonic acid (AA) (10 and 50 microM) and exposed to 24 h of hypoxia followed by 3 h of reoxygenation (H-R). H-R resulted in myocyte injury (measured on LDH release), increase in p38MAPK phosphorylation (Western analysis), augmentation of lipid peroxidation, and upregulation of MMP-1 activity (zymography) and expression (RT-PCR and Western analysis) (all P<0.01 vs. control, n=5). Pretreatment of myocytes with EPA, but not AA, resulted in a reduction in LDH release, and attenuation of p38MAPK phosphorylation and MMP-1 activity and expression in response to H-R (all P<0.05 vs. H-R alone). Pretreatment of myocytes with EPA also reduced lipid peroxidation in myocytes exposed to H-R (P<0.05 vs. H-R alone). A high concentration of EPA (50 microM) was more potent than the lower concentration of EPA (10 microM).'] Does eicosapentanoic acid inhibit hypoxia-reoxygenation-induced injury by attenuating upregulation of MMP-1 in adult rat myocytes?