The present study investigates the potential signal pathway of
acacetin in cardioprotection against
ischemia/reperfusion injury using an in vitro
hypoxia/reoxygenation model in primary cultured neonatal rat cardiomyocytes and H9C2 cardiomyoblasts. It was found that
acacetin (0.3-3 μM) significantly decreased the apoptosis and
reactive oxygen species production induced by
hypoxia/reoxygenation injury in cardiomyocytes and H9C2 cardiomyoblasts via reducing the
pro-apoptotic proteins Bax and cleaved-caspase-3 and increasing the
anti-apoptotic protein Bcl-2. In addition,
acacetin not only suppressed the release of pro-inflammatory
cytokines TLR-4 and
IL-6 induced by
hypoxia/reoxygenation injury, but also increased the secretion of anti-inflammatory
cytokine IL-10. Moreover,
acacetin increased Nrf2 and HO-1 in a concentration-dependent manner, and rescued SOD1 and SOD2 reduction induced by
hypoxia/reoxygenation insult. These beneficial effects of
acacetin disappeared in cells with silenced Nrf2, suggesting that Nrf2 activation participates in the cardioprotective effect of
acacetin against
hypoxia/reoxygenation insult. However,
acacetin-induced Nrf2 activation was not observed in cells with silenced AMPK and in ventricular tissues of rat hearts treated with the
AMPK inhibitor Compound C and subjected to
ischemia/reperfusion injury. Our results demonstrate for the first time that AMPK-mediated Nrf2 activation is involved in the cardiomyocytes protection of
acacetin against
hypoxia/reoxygenation injury by activating a series of intracellular signals involved in anti-oxidation, anti-
inflammation, and anti-apoptosis.