Acetaminophen-induced hepatic injury in mice: the role of lipid peroxidation and effects of pretreatment with coenzyme Q10 and alpha-tocopherol.

This study was performed to determine whether oxidative stress contributed to the initiation or progression of hepatic injury produced by acetaminophen (APAP). Treatment of fasted mice with APAP (400 mg/kg, I.P.) led to hepatic injury as indicated by a marked elevation of plasma alanine aminotransferase (ALT). APAP caused an increased amount of thiobarbituric acid-reactive substance (TBARS), which was accompanied by a loss of reduced forms of coenzyme Q9 (CoQ9H2) and coenzyme Q10 (CoQ10H2) functioning as antioxidants. APAP also markedly decreased hepatic reduced glutathione (GSH) levels. Pretreatment with CoQ10 (5 mg/kg, I.V.) reduced hepatic TBARS levels to 30% and plasma ALT levels to 26% of placebo pretreatment levels without affecting hepatic GSH levels at 3 h of APAP treatment. alpha-Tocopherol (alpha-Toc) (20 mg/kg, I.V.) pretreatment also reduced hepatic TBARS levels to 13% and plasma ALT levels to 27% of placebo pretreatment levels without affecting hepatic GSH levels. These results suggest that oxidative stress followed by lipid peroxidation might play a role in the pathogenesis of APAP-induced hepatic injury, and pretreatment with lipid-soluble antioxidants such as CoQ10 and alpha-Toc can limit hepatic injury produced by APAP.