Yinhuang oral liquid protects acetaminophen-induced acute liver injury by regulating the activation of autophagy and Nrf2 signaling

Abstract

This study aimed to investigate the protective effect and potential mechanism of Yinhuang oral liquid (YOL) against acetaminophen (APAP) induced liver injury in mice. C57BL/6 mice were randomly divided into control group, model group (300 mg/kg APAP), NAC group and YOL group. Mice were treated intragastrical with YOL (8 g/kg) and N-Acetylcysteine (NAC, 300 mg/kg) 6 h before and 6 h after the APAP (300 mg/kg) intraperitoneal injection. 12 h after APAP exposure, blood and liver samples were collected for subsequent testing. The results showed that APAP decreased liver index, induced liver pathological injury with hepatocytes swelling, necrosis and apoptosis and inflammatory cell infiltration. APAP exposure significantly increased serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels to 35 and 6 multiples than their original levels. YOL alleviated liver pathological damage, decreased the serum levels of ALT and AST in APAP exposure mice, and it worked better than NAC. Moreover, APAP promoted oxidative stress by increasing lipid peroxidation (MDA) and decreasing anti-oxidant enzyme activities of SOD and GSH, inhibited the mRNA levels of Nrf2, HO-1, Gclc and Gclm, and decreased the protein levels of Nrf2, HO-1 and Keap1, compared to control group. Furthermore, APAP exposure significantly down-regulated the mRNA and protein levels of autophagy related genes (Beclin-1, LC3-II, LC3-I, Atg4B, Atg5, Atg16L1 and Atg7). However, the gene levels of mTOR and p-mTOR increased, and p-ULK1 protein level decreased in liver of APAP treated mice. Additionally, YOL alleviated the oxidative injury by up-regulating Nrf2 pathway. The gene and protein levels of autophagy-related genes Beclin-1, LC3-II, LC3-I, Atg4B, Atg5, Atg16L1 and Atg7 reached the basal levels after YOL treatment. In conclusion, YOL had a protective and therapeutic role in APAP-induced liver injury in mice by activating Nrf2 signaling pathway and autophagy.

Keywords: Acetaminophen; Drug-induced liver injury; Nrf2; Oxidative stress; Yinhuang oral liquid.