Varied Effects of Carnosine and an Antioxidant-Enriched Carnosine Supplement in Paracetamol-Induced Hepatotoxicity Model in Mice.

Carnosine is widely recognized for its antioxidant and cytoprotective properties and is being increasingly used in dietary supplements. However, its effects in drug-induced liver injury remain insufficiently studied. This study aimed to investigate and compare the hepatoprotective and antioxidative effects of pure carnosine and an antioxidant-enriched commercial carnosine supplement in a murine model of paracetamol-induced hepatotoxicity. Adult male Swiss Webster mice were pretreated orally for seven days with carnosine or a commercial carnosine supplement prior to a single hepatotoxic dose of paracetamol. The serum biochemical parameters, hepatic oxidative stress markers, histopathology, and immunohistochemical expression of CYP2E1, COX-2, and Iba1 were evaluated 24 h after paracetamol administration. Paracetamol increased serum aminotransferases, lipid peroxidation, CYP2E1 expression, and histological liver injury. Pure carnosine pretreatment tended to exacerbate biochemical liver injury, whereas the commercial supplement attenuated lipid peroxidation, preserved bilirubin levels, and reduced histological damage. Both formulations decreased CYP2E1 expression and were associated with less necrosis and COX-2 immunoreactivity compared with paracetamol alone. Antioxidant enzyme activities and macrophage markers showed no consistent intergroup differences. These findings indicate that carnosine may not consistently exert hepatoprotective effects in acute drug-induced liver injury and that accompanying antioxidants may critically modify its biological actions.