Acetaminophen (APAP) overdose can cause severe liver failure even death. Nearly half of drug-induced liver injury is attributed to APAP in the US and many European countries. Oxidative stress has been validated as a critical event involved in APAP-induced liver failure. p62/SQSTM1, a selective autophagy adaptor protein, is reported to regulate Nrf2-ARE antioxidant pathway in response to oxidative stress. However, the exact role of p62-keap1-Nrf2 antioxidant pathway in APAP-induced hepatotoxicity remains unknown. In the present study, the dose-response and time-course model in C57/BL6 mice were established by intraperitoneal injection of APAP. The results of serum alanine/aspartate aminotransferases (ALT/AST) and histological examination demonstrated that APAP overdose resulted in the severe liver injury. In the meantime, the levels of p62, phospho-p62 and nuclear Nrf2 were significantly increased by APAP in mice liver, suggesting an activation of p62-keap1-Nrf2 pathway. In addition, the expression of GSTA1 mRNA was increased in a dose-dependent manner, while the mRNA levels of HO-1 and GCLC were decreased with the increase of APAP dose. Our further investigation found that expression of HO-1 and GCLC peaked at 3 h∼6 h, and then were decreased gradually. Taken together, these results indicated that p62-keap1-Nrf2 antioxidant pathway was primarily activated in the early stage of APAP hepatotoxicity, which might play a protective role in the process of APAP-induced acute liver injury.

过量服用对乙酰氨基酚（APAP）可能导致严重的肝衰竭甚至死亡。在美国和许多欧洲国家，将近一半的药物性肝损伤归因于APAP。氧化应激已被证实是APAP诱发的肝衰竭的关键事件。据报道，p62 / SQSTM1是一种选择性自噬衔接蛋白，可调节Nrf2-ARE抗氧化途径以响应氧化应激。但是，p62-keap1-Nrf2抗氧化剂途径在APAP诱导的肝毒性中的确切作用仍然未知。在本研究中，通过腹膜内注射APAP建立C57 / BL6小鼠的剂量反应和时程模型。血清丙氨酸/天冬氨酸转氨酶（ALT / AST）和组织学检查结果表明，过量服用APAP会导致严重的肝损伤。同时，p62的水平 APAP在小鼠肝脏中显着增加了磷酸化p62和核Nrf2的含量，表明p62-keap1-Nrf2途径的激活。此外，随着APAP剂量的增加，GSTA1 mRNA的表达呈剂量依赖性增加，而HO-1和GCLC的mRNA水平则降低。我们的进一步研究发现HO-1和GCLC的表达在3 h〜6 h达到峰值，然后逐渐降低。综上所述，这些结果表明p62-keap1-Nrf2抗氧化剂途径主要在APAP肝毒性的早期被激活，这可能在APAP引起的急性肝损伤过程中起保护作用。随着APAP剂量的增加，GSTA1 mRNA的表达呈剂量依赖性增加，而HO-1和GCLC的mRNA水平降低。我们的进一步研究发现HO-1和GCLC的表达在3 h〜6 h达到峰值，然后逐渐降低。综上所述，这些结果表明p62-keap1-Nrf2抗氧化剂途径主要在APAP肝毒性的早期被激活，这可能在APAP引起的急性肝损伤过程中起保护作用。随着APAP剂量的增加，GSTA1 mRNA的表达呈剂量依赖性增加，而HO-1和GCLC的mRNA水平降低。我们的进一步研究发现HO-1和GCLC的表达在3 h〜6 h达到峰值，然后逐渐降低。综上所述，这些结果表明p62-keap1-Nrf2抗氧化剂途径主要在APAP肝毒性的早期被激活，这可能在APAP引起的急性肝损伤过程中起保护作用。