Formononetin protects against concanavalin-A-induced autoimmune hepatitis in mice through its anti-apoptotic and anti-inflammatory properties.

Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease that seriously threatens the health of humans globally. Formononetin (FMN) is a natural herb extract with multiple biological functions. In this study, an experimental model of AIH was established in mice through the use of concanavalin A (ConA). To investigate the effects of FMN on ConA-induced hepatitis, the mice were pretreated with 50 or 100 mg/kg body mass of FMN. The results show that FMN alleviated ConA-induced liver injury of mice in a dose-dependent manner. Moreover, pretreatment with FMN inhibited the apoptosis of hepatocytes in the ConA-treated mice through downregulating the expression of pro-apoptotic proteins (Bax, cleaved caspase 9, and cleaved caspase 3) and upregulating the expression of anti-apoptotic protein (Bcl-2). It was also found that the levels of proinflammatory cytokines were greatly reduced in the serum and liver tissues of mice pretreated with FMN. Further studies showed that FMN reduced the level of phosphorylated nuclear factor kappa B (p-NF-κB) p65 and enhanced the level of IκBα (inhibitor of NF-κB), suggesting that FMN inhibits the activation of the NF-κB signaling pathway. In addition, FMN inhibited activation of the NOD-like receptor protein 3 (NLRP3) inflammasome. Therefore, FMN could be a promising agent for the treatment of AIH.