Introduction: Cytochrome P450 (CYP) epoxygenases metabolize arachidonic acid to epoxyeicosatrienoic acids (EETs), and which play roles in protecting myocardial ischemia/reperfusion (I/R) injury. Recent studies have shown that CYP inhibitors significantly attenuate the cardiac damage in I/R injury. However, the exact mechanism of cardioprotection by CYP inhibitors has not been elucidated. Here, we examine the effects of a nonspecific CYP inhibitor chloramphenicol (CAP) on expression of CYP2J3 and CYP2C23, and the effects of EET on downstream signaling in I/R injured rat hearts. Methods: I/R injury was induced by Langendorff model containing CAP following 30 min no-flow ischemia and 30 min reperfusion. Protein and mRNA expressions of CYP2J3, CYP2C23, PI3K and Akt were assessed by Western blotting and RT-PCR. 11,12-EET was measured by LC/MS. LDH was measured in rat hearts and BAECs. Results: I/R injury upregulated CYP2C23 expression and led to increase of LDH release and infarct size. However, CYP2J3 expression and production of 11,12-EET were reduced. CAP administration recovered CYP2J3 expression (IR, 62.84짹12.22; I/R+CAP, 103.25짹 8.26, vs. control %, p < 0.01) and production of 11,12-EET (control, 212짹18; I/R injury, 143짹21; I/R+CAP, 192짹16.08, ng/mg protein, p < 0.01). Infarct size and LDH were reduced by CAP. However CAP significantly attenuated cell death by increasing PI3K and Akt phosphorylation, these effects were abolished by Akt and PI3K inhibitors in I/R injured hearts and cultured BAECs. Conclusion: The alterations of CYP epoxygenase expression after I/R injury were reversed by CAP. CAP markedly attenuates cell death by enhancing CYP2J3 expression and production of 11,12-EET in I/R injury model and BAECs. In addition, 11,12-EET induced cell survival, at least, which is mediated through the activation of PI3K/Akt signaling pathways. These results indicate that selective enhancement of CYP2J3 and EETs may be a potential therapeutic target for ischemic heart diseases.