Objective   To study the effect of microwave irradiation on the phosphor ylation of Nrf2, a key transcription factor involved in antioxidation reaction.

  Methods   Confluent ECV 304 cells were exposed in microwave electromag netic field, 2, 4, 8, 24 h postirradiation, the following experiments were done: phosphorylation of Nrf2 were measured by immnocoprecipitation-autoradiog raphy, PKC protein expression and activity were measured by Western blot and r-³²P-AT Plabeling radioactiv ity analysis respectively.

  Results   At 2, 4, 8 h afterexposure, phospho rylation of Nrf2 were increased significantly compared with control(P < 0.05)and reached peak at 4 h and returned control level et 24 h postirradiation.Contemporarily expression of PKC were also increased and its activ ity notably enhanced 36%, 93% and 47% compared with control at 2, 4, 8 h postirradiation respectively(P < 0.05), at 24 h afterex posure the expression and activity of PKC were came down to normal.The change of PK Cactivity and Nrf2 phospho rylation had conformity in time-effect.

  Conclusion   Phosphorylation of Nrf2 in cultured endothelial cells were increased in a per iod of time afterexposure in microwave electromagnetic field and this process was concerned with PKCactivation.