| Light and magnetic field are physical factors that widely exist in the environment and play an important role in the evolution and of organisms;however,with the excessive use of artificial lighting and widespread application of magnetic fields during modern technology development,human beings have increasing chances to be exposed to stronger and stronger artificial light sources and higher and higher magnetic fields,unintentionally resulting in potential health risks and consequently causing wide concern.Existing studies have shown that light pollution caused by excessive use of artificial lighting not only affect the growth and development of animals and plants,but also seriously disrupt human body functions,causing metabolic abnormalities,neurological disorders,and tumors.With the widespread application of magnetic fields in the fields of modern medicine and scientific research,the risk of human exposure to magnetic fields has gradually increased,and the impact of magnetic fields on human health and the ecological environment has received increasing attention.Static Magnetic Field(SMF)has the characteristics of constant magnetic field intensity and direction,and its widely used in medical diagnosis,material production,welding technology,transportation,etc.,but its biological effects and mechanism are still unclear,especially the research on the influence of magnetic field intensity on the reproductive development and metabolism of organisms is relatively,scarce.In this study.Caenorhabditis elegans(C.elegans)was used as a model organism,the main objectives were to systematically study the molecular mechanism involved in light wavelength and SMF intensity affecting the lifespan,metabolism and reproduction,and explore the lipid metabolic and reproductive effects caused by co-exposure of light and magnetic field.The influence of lipid metabolism and reproductive effects provides a new experimental basis for revealing the potential health risks and interventions of light exposure and SMF exposure.The main findings were as follows:1.Effects of different wavelengths of light exposure on lipid metabolism and reproduction of C.elegans:①Light of different wavelengths(395 nm.465 nm.525 nm.590 nm,610 nm,635 nm and white light)exposure for 48 h significantly shortened the lifespan of C.elegans.②Light of different wavelengths exposure for 48 h significantly increased the triglyceride(TG)content of C.elegans,similarly the lipid droplet size and iron ion level of C.elegans.③465 nm wavelength light decreased in the expression of nematode circadian clock homologous genes lin-42,aha-1,kin-20 and nhr-85,and the fat accumulation could be dramatically suppressed by using lite-1 and gur-3 deficient strains of C.elegans.④Light of different wavelengths exposure for 48 h resulted in an increase in the number of germ cells apoptosis,a decrease in the number of oocytes,and a decrease in the number of offspring.Futhermore,short wavelengths of 395 nm and 465 nm reduced the sperm activation rate in vitro by 35.81%and 25.87%,respectively,but had no significant effect on the sperm transfer rate.The number of offspring of males exposed to 465 nm wavelength light decreased after mating with unexposed females.The above results indicate that long-term light exposure could affected the iron metabolism,lipid metabolism,and reproduction of C.elegans.2.Effects of different intensities of SMFs exposure on lipid metabolism and reproduction of C.elegans:①0.5 T SMF exposure for 48 h prolonged the lifespan of C.elegans,reduced triglyceride content and lipid droplet size,and reduced free iron ion levels.However,there was no significant effect on the in vitro activation of male sperm,premature activation and transfer of sperm.or germ cells apoptosis in C.elegans between SMF exposure group and control.0.5 T SMF exposure for 48 h up-regulated the expression of fatty acid hydrolysis genes nhr-76 and atgl-1.and down-regulated the expression of lipid synthesis genes sbp-1,fat-6 and fat-7.②4 T SMF exposure for 3 h had no significant effect on the premature activation of sperm and germ cells apoptosis,but induced the increased content of free iron ions and decreased fluorescence intensity.③After exposure to 10 T SMF for 3 h.5 h and 12 h,the size of unactivated sperm in male C.elegans was reduced,the activation of sperm was promoted in advance,the untransferred ratio of sperm was increased,the number of offspring after mating was reduced,and the offspring of hybrids was shortened.Moreover,compared with the control group,10 T SMF exposure significantly reduced the lifespan of hybrid offspring.10 T SMF exposure increased the level of free iron ions and the number of germ cells apoptosis of C.elegans,and caused oxidative stress.Different from parental N2 C.elegans at the L4 stage,which had no significant effect on the lifespan after exposure to 10 T SMF.④14 T,23 T,and 27 T SMFs exposure for 3 h increased the pemature activation rate of C.elegans sperm,similary increased the number of germ cells apoptosis,and the content of free iron ions in C.elegans.The above results showed that the medium-intensity SMF(0.5 T)could reduce fat accumulation and iron ion level after long-term exposure for 48 h,but had no obvious effect on C.elegans reproduction.High-intensity SMFs(10 T,14 T,23 T and 27 T)short-term exposure could increase the iron ion level of C.elegans,and affect the reproduction.3.Effects of co-exposure to 0.5 T SMF and light on lipid metabolism and reproduction of C.elegans:①0.5 T SMF could alleviate the shortened lifespan of C.elegans caused by 465 nm light exposure,which was prolonged by 21.41%.②0.5 T SMF alleviated the increase of triglyceride content and lipid droplet size in C.elegans caused by light exposure of different wavelengths.③0.5 T SMF exposure alleviated the increase of FTN-1::GFP ferritin caused by 465 nm light exposure,which was similar to the increase of iron ion content.④In addition,we discovered that both 0.5 T SMF and the iron ion chelator(DFO)alleviated the increase in fat accumulation induced by Ammonium ferric citrate(FAC)and 465 nm wavelength light.⑤Through liquid chromatography mass spectrometry,0.5 T SMF exposure could effectively alleviate the increase of TG and phosphatidylethanolamine(PE)of C.elegans caused by 465 nm wavelength light exposure.⑥0.5 T SMF had no significant effect on the number of germ cells apoptosis and oocytes which were increased after different wavelengths light exposure.The above results indicated that exposure to 0.5 T SMF could alleviate the disorder of lipid metabolism and abnormal iron metabolism in C.elegans caused by light by regulating iron metabolism,but had no significant effect on the reproductive changes of light.In summary,different wavelengths of light exposure increased fat accumulation.increased free iron ion levels,and affected reproduction of C.elegans.For SMFs.different intensity SMFs could trigger different biological effects on C.elegans.0.5 T SMF reduced fat accumulation and free iron ion levels of C.elegans,while there was no obvious difference on reproduction.In addition,high-intensity SMFs(10 T,14 T.23 T and 27 T)increased free iron ion level,and affected reproduction of C.elegans.More importantly,to investigate the combined biological effects after co-exposure of 0.5 T medium-intensity SMF and light,we found that 0.5 T SMF alleviated the light-induced lifespan shortening and lipid metabolism disorder.We further explored the mechanism of moderate SMF to relieve lipid metabolism disorder caused by light.discovering that light and magnetic fields could affect the lipid metabolism of C.eleguns by regulating iron metabolism.This study provides a research foundation and basis for in-depth elucidation of the effects together with mechanisms of light and SMFs on lipid metabolism and reproduction in C.elegans,which is important for more comprehensive and accurate research and evaluation of the potential environmental health risks of light and SMFs.It also provides a new experimental basis for the lipid metabolism research and potential application of the medium-intensity SMFs,which is helpful for the promotion and development of the health protection technology of the magnetic field. |
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