Electroacupuncture alleviates myocardial ischemia-reperfusion injury by targeting and inhibiting NLRP3 inflammasome-mediated cardiomyocyte pyroptosis via serum exosomal miR-22-3p

Background Myocardial ischemia-reperfusion injury (MIRI) presents a significant challenge to the effectiveness of reperfusion therapy in severe ischemic heart disease. One of the core pathological mechanisms of MIRI is NLRP3 inflammasome-mediated cardiomyocyte pyroptosis. While electroacupuncture (EA) has demonstrated efficacy in mitigating MIRI, its potential to target and inhibit NLRP3 inflammasome-mediated cardiomyocyte pyroptosis in the context of MIRI remains unclear. Additionally, the mechanism through which local EA may remotely influence the heart to alleviate MIRI is not well understood. Objective This study aims to explore the protective effects and molecular mechanisms of EA targeting NLRP3 inflammasome-mediated myocardial cell death in MIRI, focusing on the role of serum exosomes. Methods and results An animal model of MIRI was established by ligating the left anterior descending coronary artery, and EA was applied at the Neiguan (PC6) acupoint. Cardiac function, myocardial infarction area, serum myocardial enzymes, inflammatory factors, and myocardial cell pathological changes were assessed using echocardiography, Evans-TTC staining, ELISA, and H&E staining to confirm the therapeutic effect of EA in reducing MIRI. The NLRP3 agonist Nigericin was applied, and the expression levels of key genes and proteins related to NLRP3-mediated apoptosis were measured by Western blotting and RT-qPCR, confirming that EA alleviates MIRI by targeting and inhibiting NLRP3-mediated myocardial apoptosis. The role of serum exosomes in inhibiting NLRP3 inflammasome-mediated cardiomyocyte pyroptosis was then tested in a cardiomyocyte hypoxia/reoxygenation model. Exosomes from serum samples of AMI-PCI patients (with or without standard EA) and from MIRI model rats were isolated. Small RNA sequencing was performed to identify key effector miRNAs post-EA. Our findings revealed that miR-22-3p was significantly upregulated in serum exosomes following EA. Further validation demonstrated that miR-22-3p mitigates MIRI by targeting NLRP3 to inhibit cardiomyocyte pyroptosis, as confirmed through target gene prediction, in vitro cell experiments, and in vivo animal studies. Conclusion This study provides evidence that EA reduces MIRI by upregulating miR-22-3p in serum exosomes, which in turn targets and inhibits NLRP3 inflammasome-mediated cardiomyocyte pyroptosis, thereby reducing severe myocardial injury.