Idebenone reduces sepsis-induced oxidative stress and apoptosis in hepatocytes via RAGE/p38 signaling

BACKGROUND: Sepsis-induced liver dysfunction is believed to be an independent risk factor for multiple organ dysfunction and death. Idebenone (IDE), a synthetic analog of coenzyme Q10 (CoQ10), possesses an antioxidizing property. The present study aimed to investigate the efficacy of IDE on sepsis-induced liver injury and discuss its reaction mechanism in vivo and in vitro. METHODS: To establish an in vivo model of sepsis-induced liver injury, rats were treated with high-grade cecal ligation and puncture (CLP). Hematoxylin-eosin staining was applied to observe the liver pathological changes, and liver function was examined using alanine aminotransferase (ALT) and aspartate aminotransferase (AST) assay kits. Enzyme-linked immunosorbent assay (ELISA) kits were employed to assess the levels of inflammatory cytokines in serum and tissues. The activities of malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) were analyzed using MDA, SOD, and GSH-Px assay kits, respectively. The apoptosis of liver tissues was measured by terminal deoxynucleotidyl transferase-mediated nick-end labeling (TUNEL) staining, and western blot was employed to estimate apoptosis-related proteins. In vitro, 0.5 μg/mL lipopolysaccharide (LPS) was adopted to administrate primary hepatocytes. The expressions of receptor for advanced glycation end products (RAGE)/p38-related proteins were evaluated by western blot. Cell counting kit-8 (CCK-8) and dichloro-dihydro-fluorescein diacetate (DCFH-DA) assays were utilized to estimate cell viability and reactive oxygen species (ROS) content. Moreover, the transfection efficacy of overexpression (Ov)-RAGE in primary hepatocytes was tested by real-time quantitative polymerase chain reaction (RT-qPCR) and western blot. RESULTS: IDE could improve liver function and reduce sepsis-induced pathological damage. The levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) in the serum and liver tissue of sepsis rats were suppressed by IDE. Additionally, IDE repressed the oxidative stress and apoptosis of liver tissues in sepsis-induced rats. IDE also inhibited RAGE/p38 signaling. Furthermore, IDE revived the decreased viability in LPS-induced hepatocytes concentration-dependently. After overexpressing RAGE, RAGE expression in hepatocytes was significantly elevated. Further functional experiments revealed that IDE attenuated cell viability injury, apoptosis, oxidative stress, and inflammatory damage in LPS-induced hepatocytes via RAGE/p38 signaling. CONCLUSIONS: IDE helped to protect against sepsis-induced liver injury via the regulation of RAGE/p38 signaling.