Liqi Huoxue dripping pill protects against myocardial ischemia-reperfusion injury via the PI3K/Akt/GSK-3β signaling pathway in rats

Background: Liqi Huoxue dripping pill (LQHXDP), a traditional Chinese drug for coronary heart disease, has a protective effect on the heart of rats with myocardial ischemia-reperfusion injury (MIRI) in previous studies; however, its mechanism of action remains unclear. The purpose of this study was to investigate the protective mechanism of LQHXDP on MIRI in rats and its relationship with the PI3K/Akt signaling pathway. Methods: In this study, Sprague-Dawley rats were pre-infused with LQHXDP (175 mg/kg/d) for 10 days. PI3K inhibitor LY294002 (0.3 mg/kg) was intravenously injected 15 minutes before ischemia. The rat model of MIRI was established by ligating the left anterior descending coronary artery. Subsequently, cardiac hemodynamics, serum myocardial injury markers, inflammatory factors, myocardial infarct size, antioxidant indexes, myocardial histopathology, and phosphorylation levels of key proteins of PI3K/Akt signaling pathway were assessed in rats. Results: LQHXDP was found to improve cardiac hemodynamic indexes, reduce serum creatine kinase MB isoenzyme activity and cardiac troponin and heart-type fatty acid binding protein levels, lower serum interleukin-1 beta, interleukin-6 and tumour necrosis factor alpha levels, reduce the myocardial infarct size and enhance the antioxidant capacity of myocardial tissue in MIRI rats. Pathological analysis revealed that LQHXDP attenuated the extent of myocardial injury and protected mitochondria from damage in MIRI rats. Immunoblot analysis revealed that LQHXDP increased the expression levels of p-Akt and p-GSK-313 in MIRI rat cardiomyocytes. PI3K inhibitor LY294002 could impair these effects of LQHXDP. Conclusion: LQHXDP attenuated myocardial injury, attenuated oxidative stress injury and reduced inflammatory response in MIRI rats, and its protective effects were mediated by activating of PI3K/Akt/GSK-313 signaling pathway.