Molecular mechanisms of bivalirudin-induced cardioprotection in myocardial ischemia–reperfusion injury

This study aimed to examine the cardioprotective effects of bivalirudin in an in vitro model of hypoxia/reoxygenation (H/R) injury using AC16 human cardiomyocytes, with a focus on elucidating the underlying molecular pathways and key regulatory mechanisms involved. An H/R injury model was established in AC16 human cardiomyocytes. Cells were assigned to one of three groups: untreated control, H/R model, and H/R + bivalirudin intervention. Cellular proliferation and apoptosis were evaluated using the Cell Counting Kit-8 (CCK-8) assay and flow cytometry, respectively. Levels of lactate dehydrogenase (LDH), reactive oxygen species (ROS), superoxide dismutase (SOD), and malondialdehyde (MDA) were measured using biochemical assay kits. Concentrations of creatine kinase-MB (CK-MB), cardiac troponin T (cTnT), and brain natriuretic peptide (BNP) were quantified via enzyme-linked immunosorbent assay. Protein expression of ERK1/2, phosphorylated ERK1/2 (p-ERK1/2), AKT, phosphorylated AKT (p-AKT), BCL-2, BAX, and caspase-3 was assessed through Western blot analysis. Cell viability was significantly improved in the H/R + bivalirudin group relative to the H/R model group (p < 0.05). Bivalirudin notably attenuated H/R-induced elevations in intracellular ROS, MDA, and LDH levels, while restoring SOD activity (p < 0.05). Furthermore, levels of CK-MB, cTnT, and BNP were significantly reduced following bivalirudin treatment (p < 0.05). Western blot results showed increased expression of p-ERK1/2, p-AKT, and the anti-apoptotic marker BCL-2, along with decreased levels of the pro-apoptotic proteins caspase-3 and BAX (p < 0.05). Bivalirudin conferred protection against H/R-induced apoptosis in AC16 human cardiomyocytes, in part by modulating oxidative stress responses and activating the ERK1/2-MAPK and PI3K–Akt signaling pathways. These findings enhance understanding of the molecular basis of bivalirudin-mediated cardioprotection in the context of myocardial ischemia–reperfusion injury.