Effects of electromagnetic noise on the enhancement of stress-activated protein kinase(SAPK) phosphorylation induced by 50 Hz magnetic fields

Objective To investigate the possible interference effect of electromagnetic noise exposure on phosphorylation of stress activated protein kinase(SAPK) induced by 50 Hz magnetic field(MF). Methods Chinese hamster lung(CHL) cells were exposed to sham exposure(C),0.4 mT 50 Hz sinusoidal MF,0.4 mT electromagnetic noise and the combined noise MF with 50 Hz MF for 3 min and 15 min respectively.After exposure,the cells were lysed,and the proteins were extracted.The SAPK and phosphorylated SAPK(activated form of SAPK) were measured indirectly by Western blot with corresponding antibodies.The percentage of phosphorylated SAPK was calculated and analyzed. Results Exposure of cells to 50 Hz MF for 3 min and 15 min enhanced the SAPK phosphorylation.The percentage of phosphorylated SAPK were 49.3% and 57.0% respectively,and were significantly different from those of control( P 0.05, n =4).However,single noise MF exposure with the same intensity did not enhance the SAPK phosphorylation,the percentage of phosphorylated SAPK were 37.7% and 31.8%( P 0.05).When cells were exposed to the combined noise MF with 50 Hz MF for 3 min,the SAPK phosphorylation was significantly inhibited(24.4%,P0.05);for 15 min,the SAPK phosphorylation was also decreased (39.0%), but there was no significant difference from control and 50 Hz MF exposure(P0.05). Conclusion Noise MF with certain intensity could inhibit the biological effect induced by 50 Hz MF.