Melatonin confers cardioprotective effect against
myocardial ischemia/reperfusion (MI/R) injury by reducing oxidative stress. Activation of silent information regulator 1 (
SIRT1) signaling also reduces MI/R injury. We hypothesize that
melatonin may protect against MI/R injury by activating
SIRT1 signaling. This study investigated the protective effect of
melatonin treatment on MI/R heart and elucidated its potential mechanisms. Rats were exposed to
melatonin treatment in the presence or the absence of the
melatonin receptor antagonist
luzindole or
SIRT1 inhibitor EX527 and then subjected to MI/R operation.
Melatonin conferred a cardioprotective effect by improving postischemic cardiac function, decreasing
infarct size, reducing apoptotic index, diminishing serum
creatine kinase and
lactate dehydrogenase release, upregulating
SIRT1, Bcl-2 expression and downregulating Bax,
caspase-3 and cleaved
caspase-3 expression.
Melatonin treatment also resulted in reduced myocardium
superoxide generation, gp91(
phox) expression,
malondialdehyde level, and increased myocardium
superoxide dismutase (SOD) level, which indicate that the MI/R-induced oxidative stress was significantly attenuated. However, these protective effects were blocked by EX527 or
luzindole, indicating that
SIRT1 signaling and
melatonin receptor may be specifically involved in these effects. In summary, our results demonstrate that
melatonin treatment attenuates MI/R injury by reducing oxidative stress damage via activation of
SIRT1 signaling in a receptor-dependent manner.