Molecular hydrogen mitigates acetaminophen-induced liver injury and enhances the effects of N-acetylcysteine in diabetic mice

Acetaminophen (APAP) overdose induces severe liver injury, especially in diabetic patients. N-acetylcysteine (NAC) is commonly used as an approved antidote for APAP toxicity; however, its narrow therapeutic window limits its clinical utility. This study investigated the protective effects of molecular hydrogen (H₂) against APAP-induced hepatotoxicity in diabetic mice. Diabetic db/db mice were provided with hydrogen-dissolved water (H₂-water) for two weeks prior to APAP administration. Consumption of H₂-water significantly attenuated APAP-induced liver injury, as evidenced by improved histological findings and decreased plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels. Using transgenic mice expressing redox-sensitive green fluorescent protein, H₂ was shown to reduce both cytosolic and mitochondrial oxidative stress caused by APAP overdose. We observed that H₂ modulated c-Jun N-terminal kinase (JNK) activation, inhibited mitochondrial translocation of Bax, and suppressed the release of mitochondrial endonucleases. Additionally, H₂ enhanced the expression of the hepatoprotective hormone fibroblast growth factor 21 (FGF21). These findings suggest that H₂ protects against APAP-induced liver injury in diabetic mice by attenuating oxidative stress and upregulating FGF21 expression. Although NAC acts as an antioxidant, H₂ was more effective in reducing mitochondrial oxidative stress. Importantly, co-treatment with H₂ and NAC provided greater protection against APAP-induced hepatotoxicity than NAC alone. This synergistic effect may result from differences in the mechanisms by which NAC and H₂ influence FGF21 expression and mitochondrial oxidative stress. The combination of H₂ and NAC may offer an improved therapeutic strategy for treating APAP-induced liver injury in diabetic patients.