A Study Of The Effect Of Oxidative DNA Damage On Neuro-2a Cell Line Induced By 900 MHz Radiofrequency Electromagnetic Radiation

Background and Purpose:Over the past several decades,there has been a substantial increase in mobile phone use and an expansion of the number of signal base stations located near our living areas.Thus,exposure to radiofrequency electromagnetic fields(RF-EMFs)emitted from these devices has significantly increased,provoking growing concern and debate concerning the hazardous health effects of RF-EMFs exposure.The central nervous system(CNS)is considered to be one of the primary targets of this radiation,especially with regard to carcinogenicity based on a series of accumulated data.According to related studies,electromagnetic radiation can cause oxidative stress in cells,resulting in a series of cell damage,which can lead to pathological changes.In cellular damage,DNA oxidative damage(including base damage,base deletion,strand breaks,DNA-protein cross-links)may cause genetic mutations,and even lead to the occurrence of tumors and also with brain aging,Alzheimer’s disease(AD)and Parkinson syndrome(PD)and other neurodegenerative diseases.Therefore,the relationship between radio frequency electromagnetic radiation and DNA damage has become the focus of the research field in recent years.Radio frequency electromagnetic radiation induced DNA damage of cells in many reports,but its complete mechanism is not clear,900 MHz radio frequency electromagnetic radiation on DNA damage caused by the level of cell and its mechanism is poorly reported.Therefore,this study intends to investigate effects of RF-EMF on neuroblastoma cells(Neuro-2a)DNA damage and mechanism from oxidative DNA damage pathway,in order to provide more clues and basis for study on the mechanism of nerve damage caused by electromagnetic radiation.At the same time,this study also provides a better guide for the prevention,diagnosis,treatment,clinical care and family care of the related diseases.Methods:(1)Neuroblastoma cells(Neuro-2a)and grouping: We choose Neuroblastoma cell line(Neuro-2a)as the object instead of cells of the central nervous system which is commonly used for study in vitro.This cell line in the study of various harmful factors caused by neurotoxicity can be very good to show the morphology,development and changes in the signal characteristics.GSM talk mode of 900 MHz radio frequency electromagnetic radiation was set on Neuro-2a cells for 24 h,each group has a corresponding sham exposure group and control group(negative control and positive control).Exposure system is sXc-900,the frequency is 900 MHz,the specific absorption rate are 0.5 W/kg,1 W/kg,2 W/kg,continuously exposure.(2)The effect of 900 MHz radio frequency electromagnetic radiation on DNA damage of Neuro-2a cells: The CCK-8 kit was used to detect the cell viability at the end of 24 h,and the alkaline comet assay was used to detect the DNA strand breaks of Neuro-2a cells.The DCFH-DA probe was used to measure the intracellular ROS level.The FPG-modified comet assay was used to observe the degree of oxidative DNA base damage.(3)The effect of OGG1 RNA interference on oxidative DNA damage of Neuro-2a cells: To investigate whether OGG1 was involved in protecting Neuro-2a cells from RFEMFs exposure-induced DNA damage,siRNA was used to inhibit the intracellular mRNA expression of OGG1.The OGG1 expression level was quantified using RT-PCR.After down-regulation of OGG1,the CCK-8 kit was used to detect the cell viability at the same SAR of RF-EMF exposure,the alkaline comet assay and FPG-modified comet assay were used to observe the degree of oxidative DNA damage.Result:1.After exposure to 900 MHz RF-EMFs radiation for 24 h,the 2 W/kg RF-EMFs-exposed groups showed significantly increased ROS levels compared with the negative control group and the 2 W/kg sham-exposed group(p<0.05),the 2 W/kg group exhibited a significantly DNA base damage compared with the buffer-treated exposure group(p<0.05)and the FPG-treated control group(p<0.05).However,these remarkable increases were not detected in cell viability(p>0.05)and comet assay(p >0.05).2.OGG1 siRNA transfection for 24 h led to a clear decrease in OGG1 mRNA(about 67%)compared with control siRNA transfection(p<0.05).After down-regulation of OGG1,24 h of RF-EMF exposure,and corresponding to the sham exposed group and control group,significantly differences shows that the electromagnetic radiation(1 W/kg and 2 W/kg)can aggravate the damage of DNA base(p<0.05).However,the cell viability assay and comet assay showed no significant difference(P>0.05).Conclusion:In summary,DNA base damage were measured in this experimental model of radiofrequency electromagnetic radiation exposure.However,neither DNA strand breakage nor altered cell viability was observed.This study demonstrated that the down-regulation of OGG1 expression apparently exacerbates and sensitizes Neuro-2a Cells to oxidative DNA base damage induced by 900 MHz radiofrequency electromagnetic radiation.OGG1 is a major DNA glycosylase involved in the base excision repair(BER)following oxidative damage and might be a potential target for preventing RF-EMFs-induced genotoxicity.