Rhein Prevents APAP-induced drug-induced Liver Injury by Upregulating Nrf2 and Inhibiting APAP-activating Enzymes.

Severe liver injury can result from an overdose of acetaminophen (APAP). Rhein (RA) has shown a strong capability of combating inflammation and oxidative stress. Our study aimed to investigate the potential of RA in protecting the liver from APAP-induced damage and elucidate the mechanism of action. C57BL/6 mice received a pretreatment with intragastric 100 mg/kg/day RA, followed by 400 mg/kg/day APAP intraperitoneally. Liver injury was assessed via histopathology (hematoxylin and eosin (HE)-staining), serum biochemical indicators. AML-12 cells were treated with APAP or RA, and oxidative stress and apoptosis markers were evaluated. The underlying molecular mechanisms were examined by Western blotting (WB) and quantitative Real-time polymerase chain reaction (qPCR). RA treatment significantly alleviated hepatic injury caused by APAP in rodent model, reduced oxidative stress and apoptosis, and exerted a cytoprotective effect on AML-12 cells. RA increased intracellular glutathione (GSH) content and the GSH/GSSG (Glutathione disulfide) ratio, thereby enhancing the GSH redox cycle through the Nrf2 (Nuclear factor erythroid 2–related factor 2)-GCL (glutamate cysteine ligase)/GSR (glutathione-disulfide reductase) pathway. In addition, RA inhibited the expression of CYP2E1 and CYP1A2, the enzymes converting APAP into the NAPQI (N-acetyl-p-benzoquinone imine), thus effectively mitigating APAP-induced DILI (Drug Induced Liver Injury). We identified that RA prevents APAP-induced DILI liver injury by upregulating Nrf2 and inhibiting APAP-activating enzymes.