Cardioprotective effects and underlying mechanism of Radix Salvia miltiorrhiza and Lignum Dalbergia odorifera in a pig chronic myocardial ischemia model

Traditional Chinese medicines, including Radix Salvia miltiorrhiza (SM) and Lignum Dalbergia odorifera (DO) extracts, have historically been used to treat myocardial ischemia and other cardiovascular diseases. The volatile oil of DO (DOO) is one of the main components of DO. The aim of the present study was to assess the cardioprotective effects and possible underlying mechanisms of SM-DOO in pigs with ameroid constriction-induced chronic myocardial ischemia. An ameroid constrictor was placed around the left anterior descending coronary artery of pigs to induce chronic myocardial ischemia. At weeks 2, 6 and 8, myocardial injury markers and blood gas levels were detected. At week 8, coronary angiography, echocardiography and hemodynamics analysis were performed to evaluate myocardial function. Following sacrifice, myocardial tissue was collected and subjected to morphological, histopathological and apoptosis assays. Western blotting was used to detect the protein expression of Bcl-2 associated X (Bax), Bcl-2, Akt, phosphorylated (p)-Akt, glycogen synthase kinase (GSK)-3β and p-GSK-3β. It was revealed that SM-DOO treatment following chronic myocardial ischemia significantly downregulated the expression of myocardial injury markers, ameliorated myocardial oxygen consumption, increased collateralization, reduced regional cardiac dysfunction and limited the extent of myocardial damage. Furthermore, the results of an apoptosis assay revealed that the apoptosis rate was decreased, the expression of Bax decreased and Bcl-2 increased, and the ratio of Bcl-2/Bax was increased. Further experiments indicated that treatment with SM-DOO increased the phosphorylation of Akt and GSK-3β. These findings suggest that SM-DOO treatment ameliorates myocardial injury in a chronic myocardial ischemia model, and that the underlying mechanisms responsible may be associated with the activation of the Akt/GSK-3β signal pathway. Thus, experimental evidence that SM-DOO may be an effective drug for the prevention and treatment of chronic myocardial ischemia in clinical applications has been provided.