Lymphocyte Response in Human Population and its Antioxidant Protection against Low Doses of Ionizing Radiation

György J. Köteles1, Iván Bojtor1, Gabriella Bognár1, and Miklós Ótós2

1 Frédéric Joliot-Curie National Research Institute for Radiobiology and Radiohygiene, Fodor József National Center for Public Health, Budapest, Hungary
2 Atommed Ltd., Paks, Hungary


Corresponding author: Prof. György J. Köteles
    Frédéric Joliot-Curie National Research Institute for
    Radiobiology and Radiohygiene,
    Fodor József National Center for Public Health
    P.O. Box 101, H-1775 Budapest, Hungary
    Tel./Fax: (+36) 1 229 1926

CEJOEM 1999, Vol.5. No.3-4.:232-242


Key words:
Lymphocytes micronuclei, antioxidants, dose-response, human population


Abstract:
The effects of low doses ranged from 0.01 to 2 Gy were studied on human lymphocytes of various individuals. The frequency of micronuclei in cytokinesis-blocked cultured lymphocytes was taken as end-point.
    The type of probability distribution of radiation-induced increment was statistically proved as to be asymmetrical when the blood samples had been irradiated by very low doses of X-rays, i.e. in the range of 0.01-0.1 Gy, similarly to that found in unirradiated control population. On the contrary, at or above 1 Gy the normal frequency curve could be fitted in which an approx. symmetrical scatter of the increments is reflected.
    The main parameters of linear regression of the micronucleus increment on absorbed dose as the slope, the closeness of correlation between the variables in question and the proportion of variance accounted for X (i.e. R2) were analyzed when studying the dose-response relationship in each dose interval included in the whole range of 0.01-2 Gy. Beside the considerable changes experienced in dose intervals narrowed toward the lowest dose of 0.01 Gy, below a “limit” of approx. 0.2 Gy an unrelatedness was found between the absorbed dose and the increment.
    As a result of further study, certain changes in radiation-induced human lymphocyte micronucleus frequency were observed by increasing the exogenous antioxidant level in vitro with a water-soluble form of alpha-tocopherol.
    As well, the increase of antioxidants like vitamins E and C in serum of persons resulted in an increased radioresistance of their lymphocytes when tested in vitro.
    The response in very low dose range might be characterized as a peculiar response induced by a few hits. At the same time, in this dose range the biological support like increasing the antioxidant capacities and supporting the repair process of cells might help the organism to get a properly efficient protection.


Received:  03 December 1999
Accepted:  03 February 2000 

| Back |