Speaker
Dr
Pavel Marozik
(Institute of Genetics & Cytology NAS Belarus, Minsk, Belarus)
Description
For a long time it was considered that genetic effects of irradiation are related only to direct DNA damage. But a lot of evidence suggests the existence of a phenomenon of information transfer from irradiated cells to non-irradiated (radiation induced bystander effect, RIBE). The specific nature of these factors and mechanism of RIBE are still unknown. Effects of bystander factors induced in vivo in blood of people affected by the Chernobyl accident are of particular interest. For the first time such studies were performed by Dr. I. Emerit in 1990, when it was shown that blood sera from liquidators of the Chernobyl accident or residents of areas contaminated by radionuclides contained an increased level of bystander factors. In Emerit studies own lymphocytes of serum donors were used as a test-system. In the present study a new method was developed which allows evaluation of the effects of bystander factors from sera of different groups of populations on immortalized culture of human keratinocytes. This method has serious advantages as compared to that which was used earlier: used cells are not previously irradiated and could be cultivated for a longer period of time, they are more sensitive as compared to human peripheral blood lymphocytes, experiments could be easily repeated, allowing simple comparison and interpretation of the obtained results. Using this method, we evaluated the level of damaging bystander factors in blood of areas irradiated by the Chernobyl accident. Affected population groups included liquidators of the Chernobyl accident and people living and working in areas of Gomel region contaminated by radionuclides. The analysis has shown that bystander factors persist in Chernobyl liquidator blood samples for more than 20 years since irradiation. The data suggest that blood sera contain bystander factors, which are able to induce micronuclei and decrease metabolic activity of HPV-G cells. These factors could be neutralized by antioxidant substances. The discovery of the nature of such factors will facilitate better understanding of radiation damage mechanisms. Knowledge of these mechanisms is increasingly important for cancer radiation therapy –for using special correcting coefficients taking into consideration effects of bystander factors. The ability to neutralize and modify these factors may help to decrease significantly the effects of whole body radiation exposure.
Primary author
Dr
Pavel Marozik
(Institute of Genetics & Cytology NAS Belarus, Minsk, Belarus)
Co-authors
Prof.
Carmel Mothersill
(McMaster University, Hamilton, Canada)
Prof.
Irma Mosse
(Institute of Genetics & Cytology NAS Belarus, Minsk, Belarus)
