〔Abstract〕 Objective To investigate the protective effect and related mechanisms of dexmedetomidine(Dex) on iron overload toxicity in mouse hippocampal neurons(HT22) induced by ferric ammonium citrate(FAC). Methods Selected HT22 cells in good condition were randomly divided into 4 groups: control group(Ctrl group), FAC treatment group(FAC group), Dex treatment group(Dex group), ferroptosis inhibitor Fer-1 treatment group(Fer-1 group). The iron overload model was established by FAC-induced cells. Subsequently, the proliferation and survival rate of HT22 cells was detected by CCK-8 method; Western blot was used to detect the ferroptosis marker proteins prostaglandin-endoperoxide synthase 2(PTGS2) and acyl-CoA synthetase long-chain family member 4(ACSL4). The protein expressions of mammalian target of rapamycin(mTOR), transferrin receptor 1(TFR1) and ferroportin(Fpn); the gene expression levels of PTGS2 and ACSL4 in HT22 cells were detected by qPCR; Reactive oxygen species(ROS) levels in HT22 cells was detected by DHE fluorescent probe; MDA detection kit was used to detect lipid oxidation levels in HT22 cells; Mito-FerroOrange—ferrous ion probe was used to detect ferrous ion levels in HT22 cells; electron microscopy was used to detect intracellular ultrastructural changes. Results Dex group and Fer-1 group significantly decreased cell death rate after 2 h of pretreatment, the protein and gene expression levels of ferroptosis markers PTGS2 and ACSL4 significantly decreased. The degree of cell ultrastructural damage was significantly improved. The levels of ROS, lipid oxidation and Fe2+were significantly lower than those of the FAC group(P<0.05). Conclusion Dex pretreatment can attenuate FAC-induced iron overload toxicity injury in HT22 cells, which may be related to the inhibition of ferroptosis.