Aim To investigate the effects of Dexmedetomidine(DEX)on HT22 cells with hypoxia/reoxygenation based on ferroptosis and the underlying mechanism.Methods HT22 cells were used to prepare H/R injury model.In order to investigate the optimal concentration of DEX, cells were divided into five groups: control group, H/R group, low concentration(H/R+DEX2.5, 2.5 μmol·L-1), medium concentration(H/R+DEX5, 5 μmol·L-1), high concentration(H/R+DEX10, 10 μmol·L-1)DEX intervention H/R group, and the survival rates of cells were detected by MTT assay.To investigate the mechanism of the protective effects on HT22 cells with H/R injury, HT22 cells were divided into four groups: control group, H/R group, H/R+DEX5 group, and H/R+DEX5 +ML385 group.The survival rates of cells were detected by MTT assay; the levels of Fe2+ were detected by FerroOrange fluorescent probe; the C11BODIPY581/591 was used to detect the change of lipid ROS on the cells; MDA and reduced glutathione kits were used to detect the content of MDA and GSH of cells respectively.The expressions of Nrf2, GPX4, TFR1 and SLC7A11 were detected by Western blot.Results Compared with control group, the survival rate of cells, the content of GSH, and the expression of Nrf2, GPX4 and SLC7A11 all significantly decreased(all P<0.05), the level of lipid ROS, the content of MDA, the level of Fe2+, and the expression of TFR1 all significantly increased in H/R group(all P<0.01).Compared with H/R group, the survival rate of cells, the content of GSH, and the expression of Nrf2, GPX4 and SLC7A11 significantly increased(all P<0.05), the level of lipid ROS, the content of MDA, the level of Fe2+, and the expression of TFR1 significantly decreased with the treatment of DEX(all P<0.05).Compared with H/R+DEX group, the survival rate of cells, the content of GSH, and the expression of Nrf2, GPX4 and SLC7A11 markedly decreased(all P<0.05), the lipid ROS, MDA and Fe2+, and the expression of TFR1 significantly increased in H/R+DEX+ML385 group(all P<0.05).Conclusions DEX can reduce H/R injury on HT22 cells by inhibiting ferroptosis, and the mechanism might be related to the promotive expression of Nrf2.