OBJECTIVETo explore the effects of 50 Hz sinusoidal magnetic fields (MF) on secretion function of primary human villous trophoblasts in vitro, and the interference effect of "noise" MF.

METHODSThe trophoblasts were isolated from human villus by trypsin digestion and incubated in DMEM medium.Then the trophoblasts were exposed to 0.4 mT 50 Hz MF and/or "noise" MF respectively for different durations. Each exposure group was matched with one control group which was from the same villus and cultured with the same condition except the MF exposure. The concentrations of human chorionic gonadotropin (HCG) and progesterone in the culture medium were measured by immunofluorescence. Statistical significance of differences between means was determined by one way-ANOVA with P<0.05 considered significant.

RESULT50 Hz MF inhibited the HCG and progesterone secretion significantly when exposure for 72 h (compared with control group, P<0.05). There was no significant change of HCG and progesterone secretion when trophoblasts were exposed to 0.4 mT "noise" MF within 72 h (compared with control group, P>0.05). However, by superimposing the "noise" MF, the inhibition of HCG and progesterone secretion of trophoblasts induced by 50 Hz MF was eliminated.

CONCLUSIONThe exposure to 50 Hz MF for long period could inhibit trophoblasts secreting HCG and progesterone, and the "noise" MF with the same intensity could eliminate the effects induced by 50 Hz MF.