Regulation of the Keap1-Nrf2 Signaling Axis by Glycyrrhetinic Acid Promoted Oxidative Stress-Induced H 9 C 2 Cell Apoptosis.

Excessive reactive oxygen species (ROS) could interfere with the physiological capacities of H 9 C 2 cells and cause cardiomyocyte apoptosis. Glycyrrhetinic acid (GA), one of the main medicinal component of Glycyrrhetinic Radix et Rhizoma , shows toxic and adverse side effects in the clinic setting. In particular, some studies have reported that GA exerts toxic effects on H 9 C 2 cells. The purpose of this study is to assess the effect of GA-induced oxidative stress on cultured H 9 C 2 cells and reveal the relevant signaling pathways. LDH assay was used to assess cell damage. Apoptosis was detected using Hoechst 33242 and a propidium iodide (PI) assay. An Annexin V-fluorescein isothiocyanate/PI double-staining assay was utilized to investigate GA-induced apoptosis in H 9 C 2 cells. The expression level of specific genes/proteins was evaluated by RT-qPCR and Western blotting. Flow cytometry and DCFH-DA fluorescent testing were used to determine the ROS levels of H 9 C 2 cells. The potential mechanism of GA-induced cardiomyocyte injury was also investigated. GA treatment increased ROS generation and mitochondrial membrane depolarization and triggered caspase-3/9 activation and apoptosis. GA treatment also caused the nuclear translocation of NF-E2-related factor 2 after its dissociation from Keap1. This change was accompanied by a dose-dependent decline in the expression of the downstream target gene heme oxygenase-1. The findings demonstrated that GA could regulate the Keap1-Nrf2 signaling axis and induce oxidative stress to promote the apoptosis of H 9 C 2 cells.