Oxidative Stress, DNA Damage 500kV Substation Inspection Operations Research Workers And Gene Level Apoptosis

Objective:To explore the effects of power frequency electromagnetic field exposure on oxidative stress, DNA damage repair and apoptosis related genes in human peripheral blood lymphocyte, and provide a scientific basis for the health effects of power frequency electromagnetic field on workers and surrounding residents.Methods:1. Objects58power frequency electromagnetic field inspection workers in a500kV substation in Guangdong province with5years length of service were chosen as contact group.60non-exposure workers (administrative and logistics staffs) in500kV transformer substations were chosen as the control matched by the factors of gender, age, the length of service and so on.2. QuestionnairesurveyThe contents of the questionnaire includes general conditions, gender, age, cultural degree, nation, marriage condition, family income, smoking condition, drinking condition, food choosing habit, diseases history, healthy condition, medicalexposure, living history, psychological and physical stress events and related situations.3. Measurement of exposure doseThe exposure dose of electromagnetic field was measured by PMM8053A electromagnetic radiation analyzer and EHP-50power frequency magnetic field measuring probe.The individual magnetic field strength was measured with every working class of patrol workers by EMDEX MATE and EMDEX LIFE. Individual magnetic field exposure meter records were read per minute automatically, data was exported and analyzed by instrument data software and EMAC2007, personal dose measuring instrument should be worn in the chest position when inspection.4. Real-time PCRThe total mRNA was extracted by Trizol from peripheral blood lymphocytes, and MnSOD, hOGGl, Caspase-3, Bcl-2, Bax, Fas, Tp53, bcl-2/bax were detected by Real-time RT-PCR.5. Detection of plasma protein levelThe levels of Caspase-3-、8-OHdG in plasma were measured by ELISA Kit.6. Detection of activity of SOD and MDAThe activity of SOD and MDA was detected by SOD Kit and MDA Kit.7.Statistical analysisThe differences between groups were analyzed using Student’s t-test when only two groups were analyzed, or by one-way analysis of variance when more than two groups were compared. Nonparametric tests (the Mann-Whitney U test) were performed if data still do not obey the normal distribution after conversion. The influence factors on the dependent variable factors were estimated using logistic regression model with adjustment. All tests of statistical significance were two-sided (P<0.05) and were performed using the SPSS statistical software package (version13.0).Results:1.The general condition of two groupsThe average age were4.362±5.827and32.883±6.346in the exposure group and the control group, respectively. The average length of service were12.569±6.543years and12.133±6.848years in the exposure group and the control group, respectively. No statistical significant difference were found between two groups on average length of service (P>0.05); No statistical significant difference were found in sex constituent ratio, age constituentratio, working age constituent ratio, occurrencerate of physical and psychological stress events, medical exposure rate, smoking rate, quit smoking rate, drinking wine condition, drinking tea condition, food choosing habit and so on between the two groups by χ2text, respectively(P>0.05).2. The conditions of exposure dosesInspection working environment of power frequency electric field exposure dose ranges from0.0002to11.574kV/m, and the power frequency magnetic field exposure dose ranges from0.123to767.790μT. The power frequency electric field exposure dose ranges from0.0007to0.008kV/m, and the power frequency magnetic field exposure dose ranges from0.016to0.023μT in control group.The individual magnetic field strength exposure dose ranges from1.5to8.2μT in inspection worker group. Individual magnetic field strength exposure dose ranges from0.02to0.13μT in the control group.3. Comparison of related genetic level on the oxidationresistance, DNA damage repair, cellapoptosis in the two groupsNo significant difference found in SOD vitality、MDA concentration. MnSOD(△Ct)、8-OHdG concentration. hOGG1(△Ct)、caspase-3(△Ct)、6cl-2(△Ct)、bax(A Ct), fas(△Ct)、Tp53(△Ct)、bcl-2/bax(△Ct)、Caspase-3concentration (P>0.05) were found between the exposure and exposure group. Analyzed by the cumulative exposure dose H, onlyhOGG1(△Ct)discrepancy has statistical significance(P<0.05) between the high-dose group and the control group、high dose group and low dose group, and no statistical difference were found in other indexes between the two groups. The cumulative exposure dose of H did not have significant effects on the hOGG1gene expression level after adjustment for confounding factors (P>0.05). Conclusion:1.500kV transformer substation of power frequency electromagnetic field exposure has no significant effects on the antioxidant capacity of patrolling workers.2.500kV transformer substation of power frequency electromagnetic field exposure has no significant effects on the repair DNA damage of lymphocyte in patrolling workers.3.500kV transformer substation of power frequency electromagnetic field exposure has no significant effects on the apoptosis related genes of lymphocyte and level of Caspase-3in plasma in patrolling workers.