ABSTRACT
To investigate the cardioprotective effect of formononetin (FMN) on no-reflow (NR) after myocardial ischemia-reperfusion and its molecular mechanism based on integrated pharmacology and experimental verification, firstly, human breast cancer MCF-7 cells and myocardial NR rats were used to confirm the estrogenic activity and the effect of alleviating NR of FMN, respectively. Male SD rats were divided into Sham, NR, FMN (20 mg·kg-1) and sodium nitroprusside (SNP, 5.0 mg·kg-1) groups, which were administered once a day for one week, the experiment was approved by the Ethics Committee of Tianjin University of Traditional Chinese Medicine (TCM-LAEC2019095). The pharmacological analysis and in vivo study of NR rats were integrated to reveal the mechanism of FMN improving NR. The results showed that FMN had estrogenic effect and reduced NR by improving cardiac structure and function, reducing NR, ischemic myocardial area and pathological injury of cardiomyocytes. Integrated pharmacology predicts that the mechanism of FMN improving NR is mainly related to phosphatidyinositol-3-kinase-protein kinase B (PI3K-Akt) signal pathway. Phytoestrogens play a role in cardiovascular protection mainly by activating G protein-coupled estrogen receptor (GPER). GPER is also an important regulator in the upstream of PI3K-Akt signaling pathway. This study found that FMN can significantly activate GPER, p-PI3K, p-Akt and phospho-endothelial nitric oxide synthase (p-eNOS). It has good binding ability with GPER and eNOS protein. In this study, through the integration of pharmacology and experimental evaluation, it is revealed that FMN activates PI3K/Akt/eNOS signal pathway by activating GPER, thus significantly improving NR.
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.