Formononetin attenuates myocardial ischemia/reperfusion injury by regulating neutrophil extracellular traps formation and platelet activation via platelet CD36.

BACKGROUND

Prothrombotic and proinflammatory responses are crucial in the pathology of myocardial ischemia-reperfusion injury (MIRI). Platelets and neutrophil extracellular traps (NETs) are essential to linking inflammation with thrombosis. Formononetin (FMN), an isoflavone extracted from Astragalus membranaceus, has anti-inflammatory and anti-thrombotic effects and confers benefits on MIRI. However, the mechanisms of FMN against MIRI remain unclear.

PURPOSE: This study explored FMN's roles and mechanisms in modulating platelet activation and NETs formation to mitigate MIRI.

STUDY DESIGN AND

METHODS

A rat model of MIRI by the left anterior descending coronary artery ligation was utilized to evaluate the role of FMN. 60 Sprague-Dawley male rats were randomly divided into 7 groups. Proteomics, flow cytometry, immunofluorescence, ELISA, and western blotting assays were performed to reveal the potential mechanisms of FMN. Neutrophils treated with platelet-rich plasma were applied to further explore the mechanisms of FMN in vitro.

RESULTS

We showed that FMN administration declined myocardial infarct size and improved cardiac function. Moreover, FMN significantly reduced MIRI-induced platelet activation including platelet aggregation, platelet adhesion, platelet granule secretion, and platelet-leukocyte aggregation without affecting tail bleeding time. Additionally, FMN inhibited microthrombus, platelet-neutrophil aggregation, and NETs formation in myocardial tissue. Mechanistically, FMN attenuated MIRI-induced CD36 expression and phosphorylation of ERK5 in platelets. Furthermore, up-regulation of CD36 content in vitro counteracted the potency of FMN to inhibit platelet activation and NETs formation.

CONCLUSION

FMN mitigates thrombosis and inflammation in MIRI by inhibiting platelet activation and NETs formation via the CD36 pathway. This research offers important insights for future studies on MIRI prevention.