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.

The effect of lycopene supplementation on radiation-induced micronuclei in mice reticulocytes in vivo

“…In the present study, fractionated doses of 0.5 and 1 Gy administered to mice for 1 or 2 weeks induced MN both in the bone marrow and in peripheral blood RET. Induction of micronuclei in reticulocytes or polychromatic erythrocytes in mouse bone marrow or peripheral blood in vivo following irradiation were also observed previously at different doses and times of irradiation (Gandhi 2013; Bannister et al 2016; Dobrzyńska et al 2016). The frequency of micronuclei was similar for 0.5 Gy and lower for 1 Gy as compared to our earlier study, where the same doses of irradiation were used (Dobrzyńska et al 2016).…”

Diallyl Disulfide Mitigates DNA Damage and Spleen Tissue Effects After Irradiation

“…It was reported that MN formation is induced 48–72 h after irradiation [29]. In the present study, induction was still observed 3 weeks after irradiation, as well as the inhibition of induction by DADS.…”

Assessment of Genotoxicity of Citrobacter freundii Bacteriocin on Bone Marrow Cells in Albino Mice

“…This indelicate segregation of chromosomes may result from hypo-methylation of repeat sequences present in DNA, dysfunctional spindle apparatus, or irregularities in kinetochore proteins or their assembly. The resulting MN frequency could potentially arise to increased DNA repair proficiency, a decrease in the number of cellular DNA double strand breaks, an increase in cellular proliferative index, increased apoptosis of erythroblasts, or harboring DNA damage, based on the length of the erythrocyte cell cycle [35,36].…”