Basic Research On The Adverse Effects Of Electromagnetic Fields On Preimplantation And Early-pregnancy Embryos/fetus

With the advance of industrialization, environmental pollution has been bringing about a lot of health-related problems, in which some are survival-threaten for human beings. Now, concerns about the effects of environment on human especially the potential adverse effects on human reproduction are rising because reproduction is tightly related to not only this generation but also the offspring quality.In the present study, the effects of electromagnetic fields (EMF) on reproduction were evaluated as the representative of environmental physical factors. The levels of environmental EMF become higher and higher with the development of the modern society especially with the wide usage of mobile phones. Although the effects of EMF is not so severe as to cause some distinct abnormalities including stillbirth, birth defects and so on, like ionizing radiation or toxic chemicals, the low levels exposure might cause some subtle effects which cannot be ignored. The affected offsprings might survive with some functions abnormal or missed. It is most important that the abnormal function could be inherited from generation to generation.Embryos or fetus during early stage of pregnancy are most sensitive to the adverse environmental effects during the life span of human beings. The effects on embryos/fetus in this stage might cause delayed development of fetus in uterus orpotential or more severely the late-onset diseases. It is widely accepted that a normal early pregnancy is one of the most crucial aspects of the reproductive health. In the present study, some kinds of biological models of early pregnancy were built to clarify the adverse effects of EMF on reproduction, and the mechanism and possible shield methods of those effects were also explored in the levels of gene, protein and the whole body.Part OneSetting of the Models of embryo/fetus-related effects of the EMFObjective: To set some in vivo and in vitro biological models to investigate the adverse effects of EMF on preimplantation and early-pregnancy embryos/fetus. Methods: To set an in vitro model, female ICR mice were superovulated by intraperitoneal injection with PMSG (pregnant mare serum gonadotropin,), and 48 h later, they were injected with hCG (human chorionic gonadotropin) They were bred with proven breeder males and were checked the next day for a copulation plug. Females were killed and two-cell or eight-cell stage embryos were collected by flushing modified human tubal fluid. Embryos were cultured in human tubal fluid. Daily microscopic evaluation of embryos was performed. For setting an in vivo model, volunteer women in the exposure group were exposed to the RF-EMFs continuously for 1h with the antenna just placed 10cm departing from the umbilicus in the middle line of the abdomen. Placental villous tissues were taken through the cervix during dilatation and aspiration according to strict clinical procedures.Results: We obtained and cultured enough mouse embryos with high quality for subsequent research. The placental villous specimen after exposure was also obtained successfully.Conclusion: We successfully set an in vivo and in vitro models for further research.Part TwoResearch on DNA-damage Effects of EMF on Preimplantation Embryos and Underlying MechanismObjective: To investigate the effects of EMFs on DNA damage in preimplantation mouse embryos in vitro and the underlying mechanism.Methods: The formation of γH2AX foci, a new sensitive indicator for detecting DNA double-strand breaks (DSBs), was detected by immunofluorescent analysis. The development of the 2-cell and 8-cell embryos was monitored by calculating the cleavage rate.Results: The data obtained demonstrated that EMFs decreased the cleavage rate of preimplantation mouse embryos. This development-delaying effect of EMFs was related to the DNA-damaging effect indicated by the induction of γH2AX foci formation in preimplantation mouse embryos. The inducing effects of EMFs on γH2AX foci formation could be inhibited by the treatment of superimposed noise MFs or wortmannin, a phosphatidylinositol 3 (PI3) kinase family inhibitor. Furthermore, the data obtained also showed that EMFs could activate the DNA damage-repair mechanism by recruiting repair factor Rad50 to the damaged DNA sites to repair the corresponding DNA damage, however, the repair was not completely reversible.Conclusion: These findings suggest that EMFs could cause DNA damage in preimplantation embryos in vitro and that the adverse effects of EMFs on development might at least partly act through DNA damage. The DNA damage induced by EMFs could be at least partly repaired by the natural activation of DNA damage-repair mechanism or prevented by the simultaneous treatment of noise magentic fields.Part ThreeProteomic Analysis on the Alteration of Protein Expression in Early Pregnancy Tissue Exposed to Electromagnetic Fields Associated with Cell PhoneObjective: To investigate the changes of protein expression profile of early pregnancy tissue in vivo induced by radio-frequency electromagnetic fields (RF-EMF) associated with cell phones.Methods: Volunteer women about 40-60 days pregnancy were exposed to electromagnetic fields at the average absorption rate (SAR) in the range of 1.0-1.2 W/kg for 1h with the irradiation device just placed 10cm departing from the umbilicus in the middle line of the abdomen. The changes of protein profile were examined using two-dimensional electrophoresis (2-DE). And the differentiated expression proteins were identified by MALDI-TOF MS.Results: Up to 15 spots have been statistically significantly altered (their expression levels were changed at least 2 fold up or down) compared with sham-exposed group. 12 proteins were identified by MALDI-TOF MS. The proteins found were suggested to correlate with metabolism of nervous system, cellular skeleton and signal molecular so on.Conclusion: Our finding showed that RF-EMF associated with cell phones alternates the protein profile of early pregnancy tissue. The exposure might have adverse effects on cell proliferation, cell skeleton and nerves development of early stage embryos, and 2-DE coupled with MS is a promising approach to elucidate effects of RF-EMF and search for new biomarkers for environmental toxic effects.