β-Hydroxybutyrate-Induced Ferroptosis Contributes to Hepatic Oxidative Injury in Dairy Cows with Clinical Ketosis.

Ketosis is a prevalent metabolic disorder in periparturient dairy cows and severely impairs production performance. It has been established that ketotic cows manifest hepatic oxidative damage; however, the precise molecular mechanisms underlying this pathology remain elusive. The present results demonstrate that ketotic dairy cows exhibit severe hepatic oxidative damage and ferroptosis. This pathological state is characterized by aberrant hepatic iron accumulation, driven by an imbalance between increased transferrin receptor 1 (TFR1)-mediated iron uptake and decreased ferroportin (FPN)-mediated iron export. Furthermore, we observed a substantial accumulation of lipid peroxides due to both an impaired nuclear factor erythroid 2-related factor 2 (NFE2L2)/glutathione peroxidase 4 (GPX4) antioxidant pathway and enhanced acyl-CoA synthetase long-chain family member 4 (ACSL4)-mediated lipid peroxidation. In vitro, β-hydroxybutyrate (BHB) induced oxidative injury and ferroptosis in bovine hepatocytes, and the molecular patterns were consistent with those in vivo. Mechanistically, BHB disrupted TFR1/FPN-mediated iron metabolism, impaired the NFE2L2-mediated GSH synthesis pathway, and promoted ACSL4-mediated lipid peroxidation. Notably, inhibition of ferroptosis can significantly alleviate BHB-caused oxidative damage in bovine hepatocytes. In summary, these data demonstrate that BHB-induced ferroptosis is mechanistically associated with hepatic oxidative injury in ketotic dairy cows. These findings not only contribute to mechanistic insights into hepatic oxidative injury of ketotic cows but also highlight the potential of targeting ferroptosis for therapeutic intervention in ketosis.