Relationship between radioadaptive response and individual radiosensitivity to low doses of gamma radiation: an extended study of chromosome damage in blood lymphocytes of three donors

Abstract

Purpose: Our study aimed at evaluating: 1) whether well-established variability in radioadaptive response (AR) in various donor blood lymphocytes might be attributed to inter-individual differences in radiosensitivity to different low dose levels; 2) whether AR is reproducibly present over time in the lymphocytes of AR-positive individuals.

Experimental procedure: Whole blood samples of three donors were exposed to low doses (2–30 cGy) of γ-radiation alone (G₀ phase) or followed by a 1 Gy challenge dose (late S/early G₂ phase), and chromosome aberration were scored to assess the dose-response relationship and adaptive response, correspondingly. Three experiments were performed on blood samples of the same donors at six month intervals.

Results: Significant differences in dose response relationship for blood lymphocytes were found among individuals. In most cases, the donors exhibited initial low-dose hypersensitivity (HRS) followed by an increase in radioresistance (IRR). AR could be successfully induced by some particular priming doses in the lymphocytes of each donor; however, the doses resulting in a protective response were quite different for all three donors. These protective doses could equally belong to either HRS or IRR region on the individual dose-response curves. In most cases, no clear AR outcome dependence on the priming dose was found at all. Moreover, pre-exposure to the same low dose could result in opposite effects in the lymphocytes of the same donor in different experiments.

Conclusions: AR variability in human lymphocytes is not attributed to variation in radiosensitivity among individuals and is more drastic than was believed. It seems doubtful that AR is a universal phenomenon which has a consistent impact on the effects of radiation exposure on humans.

Keywords:

• γ-irradiation
• low dose
• cytogenetic radioadaptive response
• radiosensitivity

Disclosure statement

The authors stated that they have no conflicts of interest regarding the publication of this article.

Notes on contributors

Olga Komova is the Head of the group of Normal and Tumor Cell Radiobiology, Laboratory of Radiation Biology, Department of Radiation Cytology, Joint Institute for Nuclear Research. Komova’s research interests are in the field of biological effects of charged particles, cytogenetic effects of low-level ionizing radiation, radiation-induced immune response.

Eugene Krasavin is the Director of Laboratory of Radiation Biology, Joint Institute for Nuclear Research. Krasavin’s research interests are in the field of radiobiology, astrobiolology, physiology.

Elena Nasonova is the Senior Staff Scientist at Laboratory of Radiation Biology, Department of Radiation Cytology, Joint Institute for Nuclear Research. Nasonova’s research interests include cytogenetic effects of charged particles, DNA repair.

Larisa Mel'nikova is an Engineer at Laboratory of Radiation Biology, Department of Radiation Cytology, Joint Institute for Nuclear Research. Mel’nikova’s research interests include cytogenetic effects of low-level ionizing radiation.

Nina Shmakova is the Senior Staff Scientist at Laboratory of radiation biology, Department of Radiation cytology, Joint Institute for Nuclear Research. Shmakova’s research interests include cytogenetic effects of low-level ionizing radiation.

Micaela Cunha is a PhD student at Department of Radiation Sciences, PRISMA group, Université Claude Bernard, Lyon, France. Cunha’s research interests include medical physics, modeling of ionizing radiations effects.

Etienne Testa is an Associate professor at Department of Radiation Sciences, PRISMA group, Université Claude Bernard, Lyon, France. Testa’s research interests include particle physics applied to hadrontherapy, the radiobiology of light ions.

Michael Beuve is the Head of the group at Department of Radiation Sciences, PRISMA group, Université Claude Bernard, Lyon, France. Beuve’s research interests include radiotherapy physics, biophysical modeling.