This study was to probe the role of penehyclidine hydrochloride (PHC) mediating the impact of toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88)/nuclear factor-kappa B (NF-κB) signalling pathway on myocardial ischaemia-reperfusion injury (MI/RI) in rats through miR-199a-3p. The rat MI/RI model was established through ligating left anterior descending (LAD) coronary artery. PHC was injected preoperatively into the model rats, and injected with miR-199a-3p lentiviral vector or TLR4 antagonist (TAK-242). Next, cardiac function of rats was...