Abstract

Heat stress (HS), an escalating environmental threat, induces cognitive impairment, but the underlying mechanisms remain incompletely understood. This study investigated the role of ferroptosis, an iron-dependent cell death pathway, in HS-induced neurotoxicity. Using murine models and HT22 hippocampal neurons subjected to subacute HS (42.5 °C, 1 h/day, 7 days in vivo; 41 °C, 48 h in vitro), we demonstrate that HS triggers hippocampal ferroptosis. HS impaired spatial learning and memory (Morris water maze, shuttle box) and induced neuronal damage in the CA3 region. Untargeted serum metabolomics showed a systemic shift in arachidonic acid (AA) metabolism after heat stress, including decreased free AA and increased oxidized AA metabolites (5-HETE and 15(S)-HPETE). Because serum changes are peripheral correlates, we next assessed the hippocampus and observed oxidative stress (increased MDA, decreased SOD), molecular dysregulation (upregulated ACSL4, TfR1, COX2, CHAC1; downregulated GPX4, SLC7A11, RGS4), and histopathological damage. Critically, the ferroptosis inhibitor Ferrostatin-1 (Fer-1) attenuated cognitive deficits, neuronal damage, and molecular/metabolic dysregulation in vivo and in vitro. Pharmacological inhibition of ACSL4, the key enzyme incorporating peroxidation-susceptible PUFAs into membranes, using rosiglitazone, similarly suppressed ferroptosis markers, lipid peroxidation, ROS, and cell death in HT22 neurons, while restoring GPX4 expression. These findings establish that HS induces cognitive impairment via an ACSL4-driven lipid peroxidation-ferroptosis axis in hippocampal neurons, identifying ACSL4 as a potential therapeutic target for mitigating heat-related neurodegeneration.