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

• Published in: International journal of radiation biology 2018-01, Vol.94 (1), p.54-61
• Main Authors: Komova, Olga, Krasavin, Eugene, Nasonova, Elena, Mel'nikova, Larisa, Shmakova, Nina, Cunha, Micaela, Testa, Etienne, Beuve, Michaël
• Format: Article
• Language: English
• Subjects: Chemical Sciences; cytogenetic radioadaptive response; Life Sciences; low dose; Medical Physics; Physics; Radiochemistry; radiosensitivity; Space life sciences; γ-irradiation
• ISSN: 0955-3002; 1362-3095
• DOI: 10.1080/09553002.2018.1399226

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 (G 0 phase) or followed by a 1 Gy challenge dose (late S/early G 2 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.