Cardioprotective effects of melatonin against myocardial ischaemia/reperfusion injury: Activation of AMPK/Nrf2 pathway

Although reperfusion is the most effective therapy for patients with acute myocardial infarction, reperfusion injury limits the therapeutic effects of early reperfusion. Oxidative stress plays a crucial role in myocardial ischaemia/reperfusion (I/R) injury. Melatonin, a circulating hormone, is well‐known as an antioxidant in cardiovascular diseases. In this short communication, we show that melatonin significantly improves post‐ischaemic cardiac function, reduces infarct size and decreases oxidative stress. Furthermore, melatonin markedly increases AMPK activation and Nrf2 nuclear translocation. Nevertheless, these melatonin‐induced changes are abrogated by compound C. In addition, ML‐385, an Nrf2 inhibitor, also withdraws the antioxidative effects of melatonin but has little effect on AMPK activation. In conclusion, our results demonstrate that melatonin alleviates myocardial I/R injury by inhibiting oxidative stress via the AMPK/Nrf2 signalling pathway.