Nicotinic acid protects against hepatic ischemia-reperfusion injury via suppressing mitochondrial damage-induced ferroptosis.

BACKGROUND AND AIMS: Hepatic ischemia-reperfusion injury (HIRI) is a major contributor to liver dysfunction and failure, particularly in the context of liver transplantation. Its pathogenesis is primarily driven by ferroptosis, oxidative stress, and mitochondrial dysfunction. Given the interplay among these mechanisms through redox imbalance and disrupted energy metabolism, nicotinic acid (NA)-recognized for its antioxidative and metabolic regulatory properties-emerges as a promising therapeutic candidate. This study aims to investigate the protective effects of NA on HIRI and elucidate its underlying mechanisms. METHODS: An HIRI model in mice and a hypoxia/reoxygenation (H/R) model in primary hepatocytes were established to evaluate the effects of NA treatment on oxidative stress. NA was administered prior to model induction. N-acetylcysteine (NAC) was used as a comparator. Comprehensive assessments of ferroptosis, oxidative stress, mitophagy, and mitochondrial biogenesis markers were conducted using Western blotting, immunohistochemistry, immunofluorescence, and biochemical assays. RESULTS: NA pretreatment reduced serum alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase (LDH) levels, suppressed inflammation by decreasing neutrophil infiltration and macrophage activation, and mitigated oxidative stress by lowering reactive oxygen species (ROS) and malondialdehyde (MDA) levels. It enhanced antioxidant defenses, inhibited ferroptosis, and improved mitochondrial health through increased mitophagy, mitochondrial biogenesis, and mitochondrial permeability transition pore (mPTP) stabilization, leading to enhanced ATP production and mitochondrial function in HIRI. CONCLUSIONS: NA improves mitochondrial function by promoting mitophagy and mitochondrial biogenesis, which reduces ferroptosis and oxidative stress, thereby alleviating HIRI.