Myocardial ischemia/reperfusion (I/R) injury has been found to be associated with oxidative stress. Plantamajoside (PMS) is a major compound of Plantago asiatica that was reported to possess cardioprotective and antioxidant effects. The current study was designed to investigate the effect of PMS on myocardial I/R injury. Rat cardiomyocytes H9c2 cells were exposed to hypoxia/reoxygenation (H/R) to establish in vitro model of myocardial I/R injury. MTT assay proved that H9c2 cells viability was significant reduced under H/R treatment, while the reduction was ameliorated by PMS. H/R-induced ROS production in H9c2 cells was suppressed by PMS. The decreased activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in the H/R group were effectively elevated by PMS. In addition, treatment with PMS attenuated H/R-stimulated production of TNF-α, IL-6 and IL-1β in H9c2 cells. Besides, PMS significantly suppressed bax expression and caspase 3 activity, as well as increased bcl-2 expression in H/R-stimulated H9c2 cells. Furthermore, we also found that PMS significantly enhanced the activation of Akt/Nrf2/HO-1 signaling pathway and suppressed the activation of NF-κB signaling pathway in H/R-stimulated H9c2 cells. These results provided substantial evidence that PMS protected against myocardial I/R injury via attenuating oxidative stress, inflammatory response and apoptosis. The protective effects of PMS were attributed to the Akt/Nrf2/HO-1 and NF-κB signaling pathways.
Keywords: Akt/Nrf2/HO-1 pathway; Myocardial ischemia/reperfusion (I/R) injury; NF-κB pathway; inflammation; oxidative stress; plantamajoside (PMS).