OBJECTIVETo analyze the effects of high-frequency electromagnetic field (HF-EMF, 30 MHz, 0-1600 V/m) on the apoptosis and ultramicrostructure of the hippocamp and demonstrate the cytotoxicity of hippocamp.

METHODS120 Wistar female adult rats were randomly divided into ten groups based on body weight with different levels of 30 MHz electromagnetic field (0, 25, 100, 400, 1600 V/m) for eight hours daily. Five group rats were irradiated for three days. The other five group rats were irradiated for fifty-six days. Weekly the rats were continuously exposed five days. The apoptotic rate of the hippocamp was detected with TUNEL System. Meanwhile, the ultramicrostructure was observed with the transmission electron microscope.

RESULTS(1) There was no significant difference on the apoptotic rate and pathological change of the hippocamp cell between the exposure and the control groups through short term experiment (P > 0.05). (2) The apoptotic rate of the granulocyte on the DG campus of the hippocamp in the 400 V/m group and the 1600 V/m group (0.165% +/- 0.049%, 0.189% +/- 0.049% respectively) were increased significantly (P < 0.01) through inferior chronic experiment compared with the control group (0.052% +/- 0.016%). Along with the increase of radiation dose, the ultramicrostructure of the neuron cell appeared more abnormal cells. Especially there were marked change on the neuron in the 1600 V/m group.

CONCLUSIONSThere is no association between cell apoptotic rate of the hippocamp and short period exposure to HF-EMF (30 MHz, 25-1600 V/m). However inferior chronic exposures to HF-EMF might induce the cytotoxicity, especially in the high dose exposure (1600 V/m) under our experiment.