N-acetylcysteine modulates neutrophil-driven immune and metabolic pathways in steatotic liver ischemia-reperfusion injury.

Hepatic ischemia-reperfusion injury (IRI) is a complex event influenced by interconnected immune and metabolic processes. Steatotic livers are especially sensitive to IRI, but the crosstalk between innate inflammatory responses and lipid metabolic dysregulation in this context is not well understood. Using transcriptomic profiling in a murine high-fat diet (HFD) model, we assessed immune and metabolic responses to hepatic IRI and examined the effects of N-acetylcysteine (NAC). In steatotic livers, IRI induced the upregulation of inflammatory mediators, including TLR/NF-κB-associated genes (Tlr2, Tlr4, Irf1) and neutrophil-associated genes (S100a8, S100a9, Lcn2), accompanied by the downregulation of lipid and cholesterol metabolism-related genes, including Cyp7a1, Cyp8b1, Cyp27a1, and Hmgcr. NAC supplementation attenuated inflammatory gene expression and restored key lipid biosynthetic regulators. We then performed targeted lipidomic analysis to determine whether NAC-mediated transcriptional changes were reflected at the lipid level and observed a significant increase in total phosphatidylcholine and sphingomyelin in steatotic livers following IRI. Finally, to assess the contribution of innate immune cells to hepatic IRI, we quantified neutrophils and macrophages in HFD+NAC IRI and HFD IRI livers. We found that NAC supplementation reduced hepatic neutrophil accumulation and markedly decreased LCN2 expression following IRI.