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In vivo Characterization of the Radiosensitizing Effect of a Very Low Dose of BrdU in Murine Cells Exposed to Low‐Dose Radiation
Author(s) -
CruzVallejo Virginia,
OrtízMuñiz Rocío,
VallarinoKelly Teresita,
CervantesRíos Elsa,
MoralesRamírez Pedro
Publication year - 2019
Publication title -
environmental and molecular mutagenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1
H-Index - 87
eISSN - 1098-2280
pISSN - 0893-6692
DOI - 10.1002/em.22284
Subject(s) - micronucleus test , micronucleus , genotoxicity , in vivo , microbiology and biotechnology , cytotoxicity , bromodeoxyuridine , reticulocyte , mutagen , flow cytometry , bone marrow , dna damage , chemistry , biology , in vitro , toxicity , biochemistry , dna , cell growth , immunology , genetics , organic chemistry , messenger rna , gene
The aim of the present study was to characterize the in vivo radiosensitizing effect of a very low dose of bromodeoxyuridine (BrdU) in mice exposed to low‐dose radiation by establishing the following: (1) the radiosensitizing effect during DNA synthesis using single‐cell gel electrophoresis (SCGE) in murine bone marrow cells, and (2) the number and timing of the mechanisms of genotoxicity and cytotoxicity, as well as the correlation of both end points, using flow cytometry analysis of the kinetics of micronucleus induction in reticulocytes. Groups of mice received intraperitoneal injections of 0.125 mg/g of BrdU 24 h prior to irradiation with 0.5 Gy of 60 Co gamma rays. DNA breaks measured using SCGE were determined at 30 min after exposure to radiation. The kinetics of micronucleated reticulocyte (MN‐RET) induction was determined every 8 h after irradiation up to 72 h. The results from both experimental models indicated that low‐level BrdU incorporation into DNA increased the sensitivity to 0.5 Gy of radiation, particularly in the S phase. The formation of micronuclei by gamma rays was produced at three different times using two main mechanisms. In the BrdU‐substituted cells, the second mechanism was associated with a high cytotoxic effect that was absent in the irradiated BrdU‐unsubstituted cells. The third mechanism, in which micronucleus formation was increased in irradiated substituted cells compared with the irradiated nonsubstituted control cells, was also related to an increase in cytotoxicity. Environ. Mol. Mutagen. 60:534–545, 2019. © 2019 Wiley Periodicals, Inc.