Coptisine protects cardiomyocyte against hypoxia/reoxygenation-induced damage via inhibition of autophagy.

Coptisine is a natural occurring isoquinoline alkaloid isolated from the traditional Chinese medicinal herb Rhizoma coptidis. Coptisine has been reported to have protective effects on reperfusion injury in cardiomyocytes, however, the underlying mechanism remains uncertain. Here, we used a hypoxia/reoxygenation (H/R)-treated H9c2 cell model to study the protective effects of coptisine on cardiomyocyte. The results showed that NaS2O4 induced hypoxia/reoxygenation model increased apoptosis and up-regulated autophagy marker LC3-II and cleaved Caspase-3, Beclin1 and Sirt1 levels. Coptisine treatment increased cell survival, inhibited apoptosis, and reduced the protein level of LC3-II, cleaved Caspase-3, Beclin1 and Sirt1. Further, we showed that coptisine combined with chloroquine (CQ), the inhibitor of autolysosome, reduced LC3-II, suggesting that coptisine may inhibit autophagosome formation than induction of autolysosome in the autophagy events. Our results indicate that coptisine may protect cardiomyocyte damage by H/R through suppressing autophagy. Overall, our study provides a new mechanism for the treatment of coptisine on H/R-induced cardiomyocyte damage and death.