4-hydroxy-2(3H)-benzoxazolone alleviates acetaminophen-induced hepatic injury by inhibiting NF-κB and activating Nrf2/HO-1 signaling pathways

The purpose of this study is to evaluate the protective effect of 4-hydroxy-2(3H)-benzoxazolone from Acanthus ilicifolius (HBAI) on acute liver injury induced by acetaminophen in mice and its mechanism. Mice were continuously treated with HBAI (200, 100, 50 mg/kg) once a day for 10 days. After that, the mice were fasted for 8 hours, followed by intraperitoneal injection of acetaminophen (300 mg/kg). The results showed that HBAI pretreatment significantly reduced acetaminophen-induced liver tissue congestion, hepatocyte apoptosis and necrosis, and inflammatory cell infiltration. HBAI could effectively reduce the levels of serum alanine aminotransferase, aspartate aminotransferase, total bilirubin, reactive oxygen species and malondialdehyde. Interestingly, the activities of liver catalase, superoxide dismutase, glutathione and glutathione reductase were enhanced by HBAI pretreatment. Moreover, HBAI pretreatment alleviated acetaminophen-induced hepatocyte apoptosis by regulating the expression of Bcl-2 family proteins and the mitochondrial function. Further study showed that HBAI pretreatment effectively promoted the expression of Nrf2 and its signal downstream HO-1, NQO1, GCLC, GCLM, and MGST-1, suggesting the activation of the Nrf2/HO-1 signaling pathway. Meanwhile, HBAI attenuated the phosphorylation of NF-κBp65, IKKα/β, and IκBα, as well as the expression of NF-κBp50, which indicated that HBAI blocked the signal transduction of NF-κB pathway. In conclusion, HBAI protects against acetaminophen-induced acute liver injury by inhibiting the NF-κB and activating Nrf2/HO-1 signaling pathways.