Effects Of Static Magnetic Fields On Neurobehavior And Early Embryonic Development In Caenorhabditis Elegans

With the development of superconducting magnetic technology and wide application of Man-made SMFs in large-scale industry,medical diagnosis,and scientific research,the environmental health risks of SMF exposure have attracted increasing attention.Static magnetic field(SMF)is constant in intensity and direction with few variable parameters,which provides important environmental conditions and detection methods for the development of physics,chemistry,materials and biology.The clinical application of magnetic resonance brain imaging has drawn extensive attention to the neurobiological effects of SMFs.Embryo and infancy are critical periods of neurodevelopment,and in the early embryonic stage,embryonic cells divide and differentiate at a high speed,which is highly susceptible to interference from the maternal and external environmental factors.However,studies on the nervous system and early embryonic development after SMFs(especially high-intensity SMFs)exposure are extremely lacking.In this study,Caenorhabditis elegans(C.elegans)was used as the research object,the moderate-intensity SMFs(0.5 T and 1 T)generated by permanent magnets and the moderate-intensity SMFs(4 T,10 T)generated by superconducting and water-cooled magnets were used,which to study the effects and related mechanisms of different SMF conditions on neurobehavior,and to explore the response of early embryonic cells to magnetic fields.The main findings were as follows:1.Effects of moderate-intensity SMF on neurobehavior of C.elegans:Long-term exposure to 0.5 T and 1 T SMFs had no significant effect on locomotion behavior,but the aversive learning behavior was significantly decreased,and the pharyngeal pumping of C.elegans was significantly increased after 1 T SMF exposure.The level of serotonin(5-HT)in C.elegans increased significantly after exposure to 0.5 T and 1 T SMFs,while the levels of choline,γ-aminobutyric acid(GABA),and dopamine had no change.Regulation in the expression of 5-HT rate-limiting enzymes and regulator genes are responsible for changes in 5-HT levels and aversive learning behaviors,and 0.5 T and 1 T SMFs can alter fat storage via 5-HT pathway.2.Effects of high-intensity SMFs on neurobehavior and neurodevelopment of C.elegans:10 T and 27 T SMF exposure reduced locomotor behavior and aversive learning behavior of C.elegans,while the decrease meant in locomotor behavior was transient and reversible.Fluorescence imaging of the four neurotransmitter systems including choline,GABA,dopamine,and 5-HT in C.elegans showed that,excepting for reducing the level of 5-HT,10 T SMF had no significant effect on the structural integrity of the above neurotransmitter systems and the secretion of the other three neurotransmitters.Further studies found that 10 T SMF mediated changes in 5-HT levels and aversive learning behavior in C.elegans by downregulating the expression of ocr-2 and osm-9.In addition,short-term exposure to 10 T SMF in early embryos can delay the extension of neurites in vitro,but the final length of axons did not change significantly.3.Effects of high-intensity SMFs on early embryonic cell division and ontogeny of C.elegans:After exposure to high-intensity SMFs in young adult and early embryos in vivo,through the study of early embryonic cell division spindles,embryo hatching and subsequent individual reproductive development indicators,we found that high-intensity(14 T and 27 T)SMFs induced a significant increase in the formation of multipolar spindles in early embryonic cells,and decreased the developmental speed and lifespan of embryonic and postembryonic in C.elegans.High-intensity SMFs had little effect on embryo hatching rate and brood size of post-embryonic adults,only the 27 T SMF treatment group decreased slightly.Pearson’s correlation test showed that the reduction of ovulation rate,hatching rate,growth rate,offspring number and lifespan induced by high-intensity SMFs were related to the increased proportion of multipolar spindle formation in early embryonic cells.Further research found that the low expression of asymmetric cell division and spindle positioning-related genes in early embryos,as well as the abnormal expression of non-myosin NMY-2 in early embryonic division grooves,play an important role in the decrease meant of embryonic development induced by high-intensity SMFs.In conclusion,this study revealed the effects of moderate-intensity SMF on the neurobehavior and neurotransmitter system in C.elegans,and the effects of high-intensity SMF on nervous system,early embryonic cell responses and development of C.elegans;which provided a new insight into neural effects studies and potential medical applications of moderate-intensity SMFs,as well as theoretical references for environmental health risk assessment after exposure to high-intensity SMFs.