Pinocembrin inhibited cardiomyocyte pyroptosis against doxorubicin-induced cardiac dysfunction via regulating Nrf2/Sirt3 signaling pathway

Doxorubicin (DOX) is a potent chemotherapeutic drug but the clinical use was limited by its dose-dependent cardiotoxicity. Pinocembrin (PCB), a flavonoid originally isolated from honeybee propolis and rhizomes of Boesenbergia pandurate displays diverse biological activities. However, the role of PCB in DOX-induced cardiac injury and its underlying molecular mechanism are not fully elucidated. The present study was designed to evaluate the protective role of PCB in a DOX-induced cardiotoxicity in vivo and in vitro. Our results revealed that PCB administration greatly improved cardiac function and reduced cardiac fibrosis manifested by LVEF, LVFS, LVIDd, LVIDs, and myocardial fibrotic area which were impaired by DOX treatment. The cardiac injury evidenced by LDH and CK-MB activities were reduced while the levels of IL-1β and IL-18 were decreased following PCB treatment compared to DOX-treated mice. Mechanically, our present results showed that PCB significantly inhibited DOX-induced cardiomyocyte pyroptosis via activating Nrf2/Sirt3 signal pathway. Furthermore, the inhibition of Nrf2 in H9c2 cells abolished the protective role of PCB against DOX-induced cell toxicity, which was at least partly via upregulation of NLRP3-mediated pyroptosis. In conclusion, our study clearly demonstrated that PCB reduced cardiomyocyte pyroptosis to protect hearts from DOX-induced cardiotoxicity through activation of Nrf2/Sirt3 signal pathway.