Lack of Nontargeted Effects in Murine Bone Marrow after Low-Dose In Vivo X Irradiation

• Published in: Radiation research Vol. 175; no. 3; pp. 322 - 327
• Main Authors: Zyuzikov, Nikolay A., Coates, Philip J., Parry, John M., Lorimore, Sally A., Wright, Eric G.
• Format: Journal Article
• Language: English
• Published: United States The Radiation Research Society 01-03-2011; Radiation Research Society
• Subjects: Animals; Apoptosis - radiation effects; Bone marrow; Bone marrow cells; Bone Marrow Cells - cytology; Bone Marrow Cells - metabolism; Bone Marrow Cells - radiation effects; Bystander Effect - radiation effects; Chromosomal instability; Chromosomal Instability - radiation effects; Dose response relationship; Dose-Response Relationship, Radiation; Ionizing radiation; Irradiation; Linear Energy Transfer; Mice; Radiation damage; Radiation Dosage; Radiotherapy; REGULAR ARTICLES; Signal Transduction - radiation effects; Space life sciences; Stress, Physiological - radiation effects; Time Factors; Tumor Suppressor Protein p53 - metabolism; X-Rays
• ISSN: 0033-7587; 1938-5404
• DOI: 10.1667/RR2386.1

Exposure to high doses of ionizing radiation unequivocally produces adverse health effects including malignancy. At low doses the situation is much less clear, because effects are generally too small to be estimated directly by epidemiology, and extrapolation of risk and establishment of international rules and standards rely on the linear no-threshold (LNT) concept. Claims that low doses are more damaging than would be expected from LNT have been made on the basis of in vitro studies of nontargeted bystander effects and genomic instability, but relevant investigations of primary cells and tissues are limited. Here we show that after low-dose low-LET in vivo radiation exposures in the 0–100-mGy range of murine bone marrow there is no evidence of a bystander effect, assessed by p53 pathway signaling, nor is there any evidence for longer-term chromosomal instability in the bone marrow at doses below 1000 mGy. The data are not consistent with speculations based on in vitro nontargeted effects that low-dose X radiation is more damaging than would be expected from linear extrapolation.