title: Human circulating plasma DNA significantly decreases while lymphocyte DNA damage increases under chronic occupational exposure to low-dose gamma-neutron and tritium β-radiation.
abstract: The blood plasma of healthy people contains cell-fee (circulating) DNA (cfDNA). Apoptotic cells are the main source of the cfDNA. The cfDNA concentration increases in case of the organism's cell death rate increase, for example in case of exposure to high-dose ionizing radiation (IR). The objects of the present research are the blood plasma and blood lymphocytes of people, who contacted occupationally with the sources of external gamma/neutron radiation or internal β-radiation of tritium N = 176). As the controls (references), blood samples of people, who had never been occupationally subjected to the IR sources, were used (N = 109). With respect to the plasma samples of each donor there were defined: the cfDNA concentration (the cfDNA index), DNase1 activity (the DNase1 index) and titre of antibodies to DNA (the Ab DNA index). The general DNA damage in the cells was defined (using the Comet assay, the tail moment (TM) index). A chronic effect of the low-dose ionizing radiation on a human being is accompanied by the enhancement of the DNA damage in lymphocytes along with a considerable cfDNA content reduction, while the DNase1 content and concentration of antibodies to DNA (Ab DNA) increase. All the aforementioned changes were also observed in people, who had not worked with the IR sources for more than a year. The ratio cfDNA/(DNase1×Ab DNA × TM) is proposed to be used as a marker of the chronic exposure of a person to the external low-dose IR. It was formulated the assumption that the joint analysis of the cfDNA, DNase1, Ab DNA and TM values may provide the information about the human organism's cell resistivity to chronic exposure to the low-dose IR and about the development of the adaptive response in the organism that is aimed, firstly, at the effective cfDNA elimination from the blood circulation, and, secondly - at survival of the cells, including the cells with the damaged DNA.
authors.affiliation: Russian Federal Nuclear Center - All-Russian Research Institute of Experimental Physics (RFNC-VNIIEF) 607190, Sarov, 37 Mira ave., Nizhniy Novgorod Region, Russia. Electronic address: inna.korzeneva@molgen.vniief.ru.
authors.forename: Inna B
authors.initials: IB
authors.lastname: Korzeneva
authors.affiliation: Research Centre for Medical Genetics, Russian Academy of Medical Sciences, 115478 Moscow, 1 Moskvorechye str., Russia.
authors.forename: Svetlana V
authors.initials: SV
authors.lastname: Kostuyk
authors.affiliation: Research Centre for Medical Genetics, Russian Academy of Medical Sciences, 115478 Moscow, 1 Moskvorechye str., Russia.
authors.forename: Liza S
authors.initials: LS
authors.lastname: Ershova
authors.affiliation: Federal Medial and Biological Center named after Burnazyan of the Federal Medical and Biological Agency (FMBTz named after Burnazyan of FMBA), Moscow, Russia; State Research Center - Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency, Zhivopisnaya, 46, Moscow, 123098, Russia.
authors.forename: Andrian N
authors.initials: AN
authors.lastname: Osipov
authors.affiliation: Russian Federal Nuclear Center - All-Russian Research Institute of Experimental Physics (RFNC-VNIIEF) 607190, Sarov, 37 Mira ave., Nizhniy Novgorod Region, Russia.
authors.forename: Veronika F
authors.initials: VF
authors.lastname: Zhuravleva
authors.affiliation: Russian Federal Nuclear Center - All-Russian Research Institute of Experimental Physics (RFNC-VNIIEF) 607190, Sarov, 37 Mira ave., Nizhniy Novgorod Region, Russia.
authors.forename: Galina V
authors.initials: GV
authors.lastname: Pankratova
authors.affiliation: Research Centre for Medical Genetics, Russian Academy of Medical Sciences, 115478 Moscow, 1 Moskvorechye str., Russia.
authors.forename: Lev N
authors.initials: LN
authors.lastname: Porokhovnik
authors.affiliation: Research Centre for Medical Genetics, Russian Academy of Medical Sciences, 115478 Moscow, 1 Moskvorechye str., Russia.
authors.forename: Natalia N
authors.initials: NN
authors.lastname: Veiko
mesh_terms: D000328:Adult; D000368:Aged; D017209:Apoptosis / Q000528:radiation effects; D001610:Beta Particles; D020552:Comet Assay; D004247:DNA / Q000097:blood / Q000528:radiation effects*; D004249:DNA Damage / Q000528:radiation effects*; D003850:Deoxyribonuclease I / Q000378:metabolism; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005720:Gamma Rays; D006801:Humans; D008214:Lymphocytes / Q000528:radiation effects*; D008297:Male; D008875:Middle Aged; D009502:Neutrons; D055848:Nuclear Power Plants; D016273:Occupational Exposure; D012426:Russia; D014316:Tritium
chemical_list: D014316:Tritium; D004247:DNA; D003850:Deoxyribonuclease I
keywords: Cell-free DNA; DNAse 1; Gamma-neutron; Low-dose irradiation; The Comet assay; Tritium β-radiation