Effects Of Power Frequency Magnetic Fields On Mouse Oocytes Meiotic Maturation

Background:With the development of economy and society, the type and amount of environmental hazards have increased recently.In face of high birth defect rate and rising infertility rate, it’s suggested that interference of environment to reproductive security has been increasingly apparent and worrisome. Artificial power frequency magnetic fields (PFMF) have become ubiquitous both in residential and occupational area. And exposure to PFMF has been dramatically elevated, which make PFMF one of the most important physical factors influencing reproductive health. Epidemiological investigations suggested that PFMF may induce spontaneous abortion, suboptimal grow in utero, congenital anomalies, early pregnancy loss, stillbirth and other adverse outcomes. Experimental studies demonstrated preliminarily that PFMF may be associated with decreased fertility through altering ultrastructure, interfering normal process of folliculogenesis and decreasing flushed blastocysts and so on. However, the influence of PFMF on single oocytes is seldom reported. In consideration of physiological significance of oocytes which are female germ cells, further investigating the role played by PFMF on denuded oocytes cultured in vitro will be of great importance to reproductive toxicity assessment.Object:To investigate the effects of PFMF on mouse oocytes meiotic maturation in vitroMethods:Oocytes were harvested from female mice at the age of21days. Oocytes were exposed or sham-exposed to2mT PFMF for4h,12h and24h. When exposure ended, DNA damage was detected in GV oocytes by immunofluorescent assay. GV oocytes were continued to culture, and then GVBD rate and PB1extrusion rate were calculated under microscope after4h and12h respectively. Chromosome spreading experiment and immunofluorescent assay were used to observe number of chromosome and configurations of chromosome and spindle in oocytes that extruded PB1. The potential of MII oocytes for further development was determined by parthenogenetic activation rate through combined use of A23187and CHX.Results:No significantly different changes in the average number of foci per cell and percentage of positive cells were found between exposed or sham-exposed groups. PFMF didn’t have effect on GVBD rate, PB1extrusion rate, number of chromosome, and configurations of chromosome and spindle. There was no statistically significant difference in parthenogenetic activation rate between exposed and sham-exposed groups.Conclusion:PFMF application didn’t have effects on mouse oocytes meiotic maturation in vitro.