β‐LAPachone ameliorates doxorubicin‐induced cardiotoxicity via regulating autophagy and Nrf2 signalling pathways in mice

beta-LAPachone (B-LAP) is a naphthoquinone that possesses antioxidant properties. In the present investigation, the protective effect of B-LAP against doxorubicin (DOX)-induced cardiotoxicity was examined in mice. Thirty-five mice were divided into 5 groups: control group, B-LAP (5 mg/kg) group, DOX (15 mg/kg) group, DOX+B-LAP (2.5 mg/kg) group and DOX+B-LAP (5 mg/kg) group. B-LAP was administered orally for 14 days of experimental period. A single dose of DOX (15 mg/kg) was injected intraperitoneally on day 3. Cardiac function, histoarchitecture, indices of oxidative stress and circulating markers of cardiac injury were examined. B-LAP (5 mg/kg) decreased serum levels of lactate dehydrogenase (LDH), creatine kinase MB (CK-MB) and cardiac troponin I (cTnI), and ameliorated cardiac histopathological alterations. In addition to increasing cellular NAD(+) /NADH ratio, B-LAP up-regulated the cardiac levels of SIRT1, beclin-1, p-LKB1 and p-AMPK, and reduced the cardiac levels of p-mTOR, interleukin (IL)-1beta, TNF (tumour necrosis factor)-alpha and caspase-3. B-LAP also elevated the nuclear accumulation of Nrf2 and simultaneously up-regulated the protein levels of haem oxygenase (HO-1) and glutathione S-transferase (GST) in the hearts of DOX mice. While B-LAP reduced malondialdehyde concentrations in heart of DOX-treated mice, it further promoted the activities of cardiac superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT).In accordance with increased cell survival, B-LAP significantly improved the cardiac function of DOX mice. Collectively, these findings underline the protective potential of B-LAP against DOX-induced cardiotoxicity by regulating autophagy and AMPK/Nrf2 signalling pathway in mice.