Uric acid preconditioning alleviated doxorubicin induced JNK activation and Cx43 phosphorylation associated cardiotoxicity via activation of AMPK-SHP2 signaling pathway

Background: Doxorubicin is an anthracycline Antibiotic, which is effective for treating various malignancies such as leukemias and lymphomas. However, its serious cumulative dose-dependent cardiotoxicity limits its clinical application. Previous studies have shown that doxorubicin-associated cardiotoxicity is closely related to adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK). Uric acid is known to exert a strong antioxidant function and moderate protection on the nerves. However, its cardioprotective properties have not been established. This study aimed to investigate the potential effect of uric acid preconditioning on doxorubicin-induced cardiotoxicity and the involvement of AMPK signaling in this process.

Methods: An acute cardiotoxicity model of doxorubicin was established by intraperitoneal injection of a single dose of doxorubicin (20 mg/kg) in mice. Uric acid (62.5, 125, and 250 mg/kg) was intragastrically administered to mice one day before doxorubicin treatment and then continuously administered every 24 h for 8 consecutive days. The mortality rate and weight of the mice were recorded every day. Electrocardiograms (ECG) and serum biochemicals were detected with an ECG instrument and enzyme-linked immunosorbent assay kit (Elisa) respectively. A real-time cell analyzer (RTCA) was used to investigate the cytotoxicity of doxorubicin in vitro. Cell signaling was assayed by western blotting.

Results: Uric acid (125 mg/kg) preconditioning increased the survival rate and body weight of doxorubicin-treated mice. Uric acid also effectively alleviated prolongation of the doxorubicin-induced QT interval, slowed heart rate, and reduced the plasma levels of aspartate aminotransferase (AST), Lactate Dehydrogenase (LDH) and creatine kinase (CK) in plasma in mice. Moreover, uric acid strongly activated AMPK and Src homology 2 domain-containing protein tyrosine Phosphatase (SHP2), inhibiting doxorubicin-induced expression phosphorylated-c-Jun N-terminal kinases (JNK) and phosphorylated-connexin 43 (Cx43) in vitro and in vivo and effectively reversing the doxorubicin-induced decreased viability of H9C2 myocardial cells in vitro.

Conclusions: We demonstrated that uric acid preconditioning alleviated doxorubicin-induced cardiotoxicity through the AMPK-SHP2-JNK-Cx43 signaling pathway.