Scutellarin modulates Nrf2 to alleviate inflammation, pyroptosis, and ferroptosis in acetaminophen-induced hepatotoxicity.

BACKGROUND

Acetaminophen (APAP), one of the most commonly employed antipyretic analgesics worldwide, has paradoxically become a predominant cause of drug-induced liver injury (DILI) following overdose. The nuclear factor-erythroid 2-related factor 2 (Nrf2), a pivotal transcriptional regulator, is widely recognized as a promising therapeutic target for phytochemical-mediated amelioration of DILI. Scutellarin (Scu), a bioactive flavonoid isolated and purified from Erigeron breviscapus (Vant.) Hand.-Mazz. (Asteraceae), demonstrates pleiotropic pharmacological activities. Nevertheless, it remains to be elucidated whether Scu can activate the Nrf2 signaling pathway to exert hepatoprotective effects against APAP-induced hepatic injury.

PURPOSE: The aim of this study was to find out how Scu protects against APAP-induced hepatotoxicity at the molecular level.

METHODS

In vivo experiments were conducted using male wild-type (WT) and Nrf2-knockout (Nrf2-/-) C57BL/6 mice. All animals were intragastrically administered APAP (400 mg/kg body weight) with or without co-administration of Scu at graded doses (90 mg/kg, 60 mg/kg or 30 mg/kg). For in vitro validation, AML12 hepatocytes were employed to investigate the protective effects of Scu against APAP-induced hepatotoxicity and its molecular mechanisms. Additionally, molecular docking was performed to characterize the potential interactions between Scu and Nrf2-related proteins.

RESULTS

The results demonstrated that APAP induced significant mortality and hepatotoxicity in mice, whereas Scu treatment effectively reduced mortality rates and attenuated hepatic damage. Scu administration notably ameliorated hepatic injury through simultaneous suppression of pro-inflammatory mediators, oxidative stress, apoptosis, pyroptosis, and ferroptosis, which was associated with the modulation of the TLR4-NF-κB/MAPK and NLRP3/caspase-1/GSDMD signaling cascades. Molecular docking analysis revealed that Scu exhibited high-affinity binding to specific domains of Nrf2, thereby potentiating its activation and nuclear translocation. Furthermore, Scu treatment significantly enhanced both the Nrf2-mediated antioxidant signaling pathway and the xCT/GPX4 axis. However, these cytoprotective effects were completely abolished in Nrf2-/- mice.

CONCLUSION

This study revealed the protective effect of Scu on APAP-induced liver injury; these effects are closely linked to Nrf2 activation, suggesting that DILI may have new drugs or therapeutic strategies.