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The time-course of micronucleated polychromatic erythrocytes in mouse bone marrow and peripheral blood
L Abramsson-Zetterberg1, G Zetterberg, J Grawé
1Department of Genetics, Uppsala University, Sweden.
Abstract:
The time-course of micronucleated polychromatic erythrocytes (MPCE) in mouse bone marrow and peripheral blood, induced by an acute 0.1 Gy dose of X-rays, was determined using flow cytometric analysis, which made frequent sampling possible and allowed use of a dose low enough not to affect erythroid cell proliferation. The frequency of MPCE (fMPCE) began to increase in the bone marrow at 10 h after irradiation and reached a maximum at 28 h after irradiation. In the peripheral blood fMPCE began to increase at 20 h after irradiation and peaked at about 40 h after irradiation. The time-course found is discussed on the basis of data on the differentiation of erythroid cells. The results indicate that the micronuclei registered in polychromatic erythrocytes may originate from lesions induced not only during the last cell cycle but also during earlier ones. After an acute dose of 1.0 Gy of X-rays the maximum fMPCE was delayed both in bone marrow and peripheral blood reflecting an effect on the cell cycle progression of erythroblasts.
Insights
X-rays induce micronucleated polychromatic erythrocytes (MPCE) in mice, detectable via flow cytometry. The study tracks MPCE frequency over time, revealing insights into DNA damage and erythroid cell differentiation.
Area of Science:
- Radiation biology
- Hematology
- Genotoxicology
Background:
- Micronuclei in erythrocytes are biomarkers of genotoxicity.
- Understanding the kinetics of micronucleus formation is crucial for assessing radiation effects.
- Flow cytometry enables precise and frequent measurement of micronucleated polychromatic erythrocytes (MPCE).
Purpose of the Study:
- To determine the time-course of MPCE formation in mouse bone marrow and peripheral blood after acute X-ray exposure.
- To investigate the relationship between radiation dose, MPCE kinetics, and erythroid cell proliferation.
- To explore the origin of micronuclei in relation to cell cycle stages.
Main Methods:
- Mice were exposed to acute doses of X-rays (0.1 Gy and 1.0 Gy).
- Micronucleated polychromatic erythrocytes (MPCE) frequency was analyzed using flow cytometry.
- Blood and bone marrow samples were collected at various time points post-irradiation.
Main Results:
- MPCE frequency increased in bone marrow starting at 10 hours, peaking at 28 hours after 0.1 Gy X-ray exposure.
- In peripheral blood, MPCE frequency increased at 20 hours, peaking around 40 hours after 0.1 Gy X-ray exposure.
- A higher dose (1.0 Gy) delayed MPCE peak frequency, indicating an impact on erythroblast cell cycle progression.
Conclusions:
- The observed time-course of MPCE formation is consistent with erythroid cell differentiation kinetics.
- Micronuclei in polychromatic erythrocytes can arise from DNA damage in earlier cell cycles, not just the terminal one.
- Radiation exposure, particularly at higher doses, affects erythroblast cell cycle progression, influencing MPCE kinetics.