Estrogen induces cardioprotection in male C57BL/6J mice after acute myocardial infarction via decreased activity of matrix metalloproteinase-9 and increased Akt-Bcl-2 anti-apoptotic signaling.

In general, young men have a greater risk than age-matched women for many types of cardiovascular diseases, including ischemic heart diseases, such as acute or chronic myocardial infarction (MI)-induced heart failure. The effects of estrogen-replacement therapy in men have not been extensively studied. We evaluated the cardioprotective effects of supplemental estrogen against left anterior descending coronary ligation-induced MI in male C57BL/6J mice. A significantly lower prevalence of cardiac rupture was observed in estrogen-treated mice regardless of castration status. A reduced prevalence of cardiac rupture was associated with decreased activities of matrix metalloproteinase 9 (MMP-9) and increased expression of the anti-apoptotic gene Bcl-2. In vitro studies using H9C2 cells under simulated ischemia re-oxygenation treatment further support the role of estrogen receptor β in estrogen-mediated cardioprotection through the Akt-Bcl-2 signaling pathway.