Salvianolic acid B inhibits myocardial I/R-induced ROS generation and cell apoptosis by regulating the TRIM8/GPX1 pathway

CONTEXT: Salvianolic acid B (SalB) can attenuate myocardial ischemia/reperfusion (I/R) injury, but the mechanisms are not entirely known. OBJECTIVE: Our study investigates if SalB protects cardiomyocytes against I/R injury by regulating Tripartite motif (TRIM) protein. MATERIALS AND METHODS: AC16 cardiomyocytes were treated with I/R, and then with SalB (10, 25 and 50 μM) for 24 h, while control cells were cultured under normal conditions. Female Sprague-Dawley rats were subjected to I/R injury, and then intravenously injected with 20, 40, or 60 mg/kg SalB or saline, as a control, rats received sham operation and saline injection. RESULTS: Upon treatment, apoptotic rate, reactive oxygen species (ROS), and malondialdehyde (MDA) were increased 10-, 3.8-, and 1.3-fold, respectively, while superoxide dismutase (SOD) activity was reduced by 62.1% compared to control cells. I/R treatment elevated the mRNA and protein expression of TRIM8. SalB treatment remarkably abolished the above-mentioned effects of I/R treatment. TRIM8 knock-down could partially alleviate I/R-induced myocardial injury. TRIM8 overexpression promoted cardiomyocyte injury, which was alleviated by SalB. Moreover, TRIM8 negatively regulated protein expression of antioxidant enzyme glutathione peroxidase 1 (GPX1). TRIM8 protein interacted with GPX1 and TRIM8 overexpression promoted GPX1 ubiquitnation. GPX1 knock-down abolished the protective effects of SalB on I/R-injured cardiomyocytes. Our in vivo experiments confirmed the effects of SalB on I/R-induced myocardial injury. DISCUSSION AND CONCLUSIONS: SalB protected cardiomyocytes from I/R-induced apoptosis and oxidative stress in vitro and in vivo, which was partly mediated by the TRIM8/GPX1 axis. This suggests that down-regulation of TRIM8 expression may ameliorate I/R-induced myocardial injury.