Nitrate protects against methotrexate-induced liver injury by activating Wnt/β-catenin Signaling in mice.

Methotrexate (MTX) is a drug used to treat autoimmune diseases and certain cancers. However, its untreatable hepatotoxic effect severely limits its clinical use. Therefore, further studies are required to combat MTX-induced liver injury. Nitrate, abundant in green vegetables, possesses anti-inflammatory, antioxidant, and immunoregulatory effects. Our study investigated the preventive effects of nitrate on MTX-induced liver injury. Liver injury in mice was induced by administering a single dose of MTX (20 mg/kg body weight) intraperitoneally (i.p.). Pre-treatment of mice with 2 mM nitrate in drinking water 5 days prior effectively mitigated the MTX-elevated serum aminotransferase activities, attenuated hepatic pathological injury, reduced hepatic apoptosis and restored the proliferative capacity of hepatocytes. RNA sequencing analysis indicated that the molecular mechanism may involve the activation of the Wnt/β-catenin pathway. The AML 12 cell line was employed for in vitro validation. In this study, the hepatoprotective effect of nitrate against drug-induced liver injury (DILI) was identified for the first time, providing a new approach to preventing DILI in clinical practice.