Mechanism of Tongmai Yangxin pill to reduce the no-reflow after myocardial ischemia and reperfusion by activating HIF-1α/eNOS signaling pathway up-regulated by GPER / 药学学报

ABSTRACT

The Tongmai Yangxin pill (TMYX) has potential clinical effects on no-reflow (NR); however, the effective substances and mechanisms by which this occurs remain unclear. This study evaluates the cardioprotective effects and molecular mechanisms of TMYX against NR. We used a myocardial NR rat model (2 h after myocardial ischemia and 2 h after reperfusion) to confirm the effect and mechanism of action of TMYX in alleviating NR. In vitro studies in isolated coronary microvasculature of NR rats and in silico network pharmacology analyses were performed to reveal the underlying mechanisms of TMYX and determine the main components, targets, and pathways of TMYX, respectively. The experiment was approved by the Ethics Committee of Hunan University of Chinese Medicine (LLBH-202212160001). TMYX showed therapeutic effects on NR by improving cardiac structure and function, reducing NR, ischemic areas, and cardiomyocyte injury, and decreasing the content of cardiac troponin I (cTnI). Moreover, the mechanism of TMYX predicted by network pharmacology is related to the hypoxia inducible factor-1 (HIF-1), nuclear factor kappa-B (NF-κB), and tumor necrosis factor (TNF) signaling pathways. TMYX increased the expression of G protein-coupled estrogen receptor (GPER), phospho-extracellular signal-regulated kinase (p-ERK), and HIF-1α. In vitro, TMYX enhanced the diastolic function of coronary microvascular cells; however, this effect was inhibited by GPER inhibitor (G-15), eNOS inhibitor (L-NAME), and sGC inhibitor (ODQ). This study integrates pharmacology and experimental evaluation to reveal that TMYX activates HIF-1α/eNOS signaling pathway by upregulating GPER to relax coronary microvessels, thereby significantly alleviating NR.