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
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