ELECTROMAGNETIC-FIELDS ENHANCE CHEMICALLY-INDUCED HYPERPLOIDY IN MAMMALIAN OOCYTES

Epidemiological studies suggest that exposure to electromagnetic field s (EMFs) in the environment may be associated with mutagenic changes, but the relation between EMF exposure and aneuploidy has not previousl y been studied. Environmental EMFs apparently lack the energy necessar y to function as aneugens, but the possibility exists that EMFs could influence the incidence of aneuploidy synergistically because EMFs can activate the neuroendocrine system, and ovulation and oocyte meiotic maturation are under neurohormonal control, This hypothesis was tested by examining the effect of EMF exposure on the occurrence of hyperplo idy in mouse oocytes induced by vinblastine sulphate (VBS), which was employed as a surrogate for aneugens in the environment. The incidence of hyperploidy in metaphase II oocytes of individual mice following s uperovulation was determined, and statistical methods were developed t o assess whether EMF exposure during oogenesis in the presence of VBS altered the rate of hyperploidy. A significant effect of EMF exposure on VBS-induced hyperploidy was found (P < 0.05), The data suggested th at the EMF primarily affected the mice that exhibited a high incidence of VBS-induced hyperploidy, Exposure had no effect on the number of o ocytes ovulated nor on the occurrence of hypoploidy. The results suppo rt the hypothesis that EMF exposure can promote the occurrence of aneu ploidy caused by an aneugen via a mechanism involving the neuroendocri ne system.