Mechanism Investigation of Tianxiangdan Against Myocardial Ischemia Based on Network Pharmacology, Molecular Docking, and in vitro Experimental

Objectives: Tianxiangdan capsule (TXD) has been clinically used in the treatment of coronary heart disease angina pectoris. This study aimed to evaluate the mechanisms of TXD against myocardial ischemia and provide evidence for its subsequent clinical application. Materials and Methods: Active components and mechanisms of action of TXD against myocardial ischemia were predicted and analyzed by network pharmacology and molecular docking. The chemical constituents in TXD were determined by HPLC-MS. The oxidative damage model was established using H2O2, which caused myocardial ischemia damage. The MTT assay and Hoechst 33342 staining were used to evaluate cell viability, while cleaved caspase-3 immunofluorescence staining was used to determine cell apoptosis. The fluorescent probe method detected ROS and intracellular Ca2+, while spectrophotometry was used to measure SOD, MDA, and NO levels in myocardial cells. Western blotting was used to detect the expression levels of ERalpha, PI3K, p-PI3K, AKT, p-AKT, and eNOS in cells. Results: It was found that TXD plays a protective role in myocardial ischemia through the estrogen pathway. The TXD drug-containing plasma exhibited increased cell survival rates and suppressed MDA levels, elevated SOD and NO levels, and significantly suppressed ROS levels as well as intracellular Ca2+ levels. Moreover, the TXD drug-containing plasma pretreated cells had significantly suppressed PI3K, p-PI3K, AKT, and p-AKT expression levels, as well as elevated ERalpha and eNOS expression levels. Conclusion: TXD activates estrogen receptor ERalpha, enhances NO release of cardiomyocytes through the estrogen signaling pathway, improves intracellular Ca2+ overload, oxidative stress injury, and apoptosis, and plays a protective role in myocardial ischemia injury.