This paper reports regulation of hypoxia inducible factor-1 α( HIF-1 α ) in hepatoma cells by irradiation. Cobalt chloride(CoCl2)

a chemical mimic agent for hypoxia research

was utilized to induce the stable expression of HIF-1 α in HepG2 cells. The HepG2 cells were irradiated to different doses to observe the changes of HIF-1 α . The level of intracellular reactive oxygen species(ROS) was assayed by fluorescent microscope and flow cytometry(FCM) . The results showed that there were obvious changes in expression of HIF-1 α after HepG2 cells exposed to radiation

and the changes were positively related with the irradiation dose from 1Gy to 5Gy. Moreover

contents of incellular ROS were negatively correlated with above levels of HIF-1 α from 1Gy to 3Gy. The results indicate that irradiation may enhance hypoxic cells HIF-1 α

and the reduction of intracellular ROS can contribute to the regulation of ionizing radiation on HIF-1 α .