title: Dose and Radioadaptive Response Analysis of Micronucleus Induction in Mouse Bone Marrow.
abstract: Enhanced cellular DNA repair efficiency and suppression of genomic instability have been proposed as mechanisms underlying radio-adaptive responses following low-dose radiation exposures. We previously showed that low-dose γ irradiation does not generate radio-adaptation by lowering radiation-induced cytogenetic damage in mouse spleen. Since radiation may exert tissue-specific effects, we extended these results here by examining the effects of γ radiation on cytogenetic damage and proliferative index in bone marrow erythrocytes of C57BL/6 and BALB/c mice. In C57BL/6 mice, the induction of micronuclei in polychromatic erythrocytes (MN-PCE) was observed at radiation doses of 100 mGy and greater, and suppression of erythroblast maturation occurred at doses of >500 mGy. A linear dose-response relationship for MN-PCE frequencies in C57BL/6 mice was established for radiation doses between 100 mGy and 1 Gy, with departure from linearity at doses of >1 Gy. BALB/c mice exhibited increased MN-PCE frequencies above baseline following a 20 mGy radiation exposure but did not exhibit radio-sensitivity relative to C57BL/6 mice following 2 Gy exposure. Radio-adaptation of bone marrow erythrocytes was not observed in either strain of mice exposed to low-dose priming γ irradiation (single doses of 20 mGy or 100 mGy or multiple 20 mGy doses) administered at various times prior to acute 2 Gy irradiation, confirming the lack of radio-adaptive response for induction of cytogenetic damage or suppression or erythrocyte proliferation/maturation in bone marrow of these mouse strains.
authors.affiliation: Canadian Nuclear Laboratories, Radiobiology and Health, Chalk River, ON K0J1J0, Canada. laura.bannister@cnl.ca.
authors.forename: Laura A
authors.initials: LA
authors.lastname: Bannister
authors.affiliation: Canadian Nuclear Laboratories, Radiobiology and Health, Chalk River, ON K0J1J0, Canada. rebecca.mantha@cnl.ca.
authors.forename: Rebecca R
authors.initials: RR
authors.lastname: Mantha
authors.affiliation: Canadian Nuclear Laboratories, Radiobiology and Health, Chalk River, ON K0J1J0, Canada. yvonne.devantier@cnl.ca.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Devantier
authors.affiliation: Canadian Nuclear Laboratories, Radiobiology and Health, Chalk River, ON K0J1J0, Canada. jenya.petoukhov@gmail.com.
authors.forename: Eugenia S
authors.initials: ES
authors.lastname: Petoukhov
authors.affiliation: Canadian Nuclear Laboratories, Radiobiology and Health, Chalk River, ON K0J1J0, Canada. bridech@ecolecatholique.ca.
authors.forename: Chantal L A
authors.initials: CL
authors.lastname: Brideau
authors.affiliation: Canadian Nuclear Laboratories, Radiobiology and Health, Chalk River, ON K0J1J0, Canada. mandy.serran@cnl.ca.
authors.forename: Mandy L
authors.initials: ML
authors.lastname: Serran
authors.affiliation: Canadian Nuclear Laboratories, Radiobiology and Health, Chalk River, ON K0J1J0, Canada. dmitry.klokov@cnl.ca.
authors.forename: Dmitry Y
authors.initials: DY
authors.lastname: Klokov
mesh_terms: D000222:Adaptation, Physiological / Q000528:radiation effects; D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology* / Q000528:radiation effects; D002467:Cell Nucleus / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D004912:Erythrocytes / Q000166:cytology / Q000528:radiation effects*; D005720:Gamma Rays; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D048629:Micronuclei, Chromosome-Defective; D015162:Micronucleus Tests; D011829:Radiation Dosage
keywords: BALB/c; C57BL/6; bone marrow; cytogenetic damage; dose–response; erythrocyte; ionizing radiation; micronucleus; mouse; radio-adaptive response