Dexmedetomidine Attenuates FAC-induced Nerve Injury By Inhibiting Ferroptosis In HT22 Cells

Background:With the intensification of the aging of the social population,the incidence of neurodegenerative diseases,such as Alzheimer’s disease and Parkinson’s disease,has been increasing year by year,which affects social development and family happiness.Therefore,researchers have paid more and more attention in recent years.Numerous studies have confirmed that the occurrence of this type of disease is closely related to iron overload and oxidative stress in neuronal cells,and neuronal iron accumulation has been observed in several neurodegenerative diseases.In microglia and astrocytes in the cortex,cerebellum,hippocampus,basal ganglia,and amygdala,histochemically detected iron deposits generally increased with age.Excessive levels of iron in the brain can lead to increased levels of lipid oxidation,resulting in nerve cell damage and even death—a phenomenon named ferroptosis by scholars.Ferroptosis plays a dominant role in the pathogenesis of neurodegenerative diseases.Dexmedetomidine,as a highly selectiveα2adrenergic receptor agonist,can improve the abnormal increase of oxidative stress levels in neurodegenerative diseases and traumatic brain injury,and is often used as a protective drug in basic experiments.Mouse hippocampal neurons,which perform cognitive functions in the central nervous system,are susceptible to stress stimulation,especially iron ion stimulation,which induces oxidative stress and induces ferroptosis,leading to neuronal damage.Aim:In this study,FAC-induced iron overload toxicity contributed to ferroptosis,and to explore the protective effect and related mechanism of dexmedetomidine on FAC-induced iron overload toxicity in HT22 cells.Methods:HT22 cells were cultured at 37℃in 5%CO₂ incubator according to conventional cell culture standards,and tested after 1:3 passaging for 12 hours at 80%-90%density of cell apposition.HT22 cells were pretreated with dexmedetomidine for 2hours and treated with 125μmol/L^-1 FAC for 24hours,followed by observation of HT22cell morphology,cell proliferation survival,intracellular reactive oxygen species production,intracellular lipid peroxidation,intracellular ferrous ion alteration,intracellular ultrastructure damage and ferroptosis specific marker PTGS2,ACSL4transcript levels.The levels of PTGS2,ACSL4,TFR1,Ferrtin and Fpn proteins were measured using western blotting.HT22 cells were treated with m TOR dual inhibitor AZD8055 to down-regulate m TOR expression and treated with 125μmol/L^-1FAC for 24hours,after which TFR1,Ferrtin and Fpn protein expression levels were detected.Results:The dexmedetomidine group showed a significant increase in cell survival compared with the FAC group,caused a significant decrease in intracellular ferrous ions,ROS levels and lipid oxidation levels,and a significant decrease in the expression of iron death markers PTGS2 and ACSL4 protein and transcript levels.m TOR expression levels in HT22 cells were downregulated after inhibition using AZD8055,and the expression levels of m TOR in HT22 cells were downregulated,the expression levels of TFR1,a protein downstream of this signaling pathway,were detected by Western blotting.m TOR expression was decreased in the cells treated with AZD8055 compared to the FAC group.m TOR expression was decreased to accelerate the occurrence of ferroptosis.Conclusion:Dexmedetomidine can inhibit iron overload-induced neurotoxicity and also better inhibit iron overload-induced aggregation of ROS,lipid oxidation levels and ferrous ions in HT22 cells and inhibit ferroptosis caused by iron overload.Compared with the Ctrl group,the reduction of m TOR expression in AZD8055-treated cells could contribute to ferroptosis in HT22 cells,and this mechanism may be through the regulation of m TOR signaling pathway.