Abstract: To study the effect of magnesium sulfate on the expression of NF - κ B and ICAM-1, and to explore the protective mechanism of magnesium sulfate on radiation injury of HUVECs. The cells under exponential growth phase were divided into control group, irradiation group and irradiation+MgSO₄ group, and treated with a single 4 Gy X-ray except the control group, while 1.25 mg/mL was added to the irradiation+MgSO₄ group 0.5 h before the irradiation. Flow cytometry analysis and RT-PCR were used to study the expression of NF-κB/ICAM-1 mRNA, and NF-κB/ICAM-1 protein expression was detected by Western blot and the laser confocal microscope. The results showed that within 72 hours after irradiation, the expression levels of NF-κB、ICAM-1 mRNA were higher than that of control group, especially for 3 h;48 h and 72 h post-irradiation. The protein level of NF-κB/ ICAM-1 Proteins expression in the group of treated by 1.25 mg/mL MgSO₄ was significantly lower than that of the controls. These results indicate that ionizing radiation can induce the over expression of NF-κB/ICAM-1, and MgSO₄ down-regulation the expression of ICAM-1 by inhibited the trans-location of NF-κB, which may be the mechanisms of radiation protection.

Key words: MgSO₄, human umbilical vein endothelial, radiation, ICAM-1, NF-κB