Chromosomal radiosensitivity study of temporary nuclear workers and the support of the adaptive response induced by occupational exposure.
OBJECTIVE
To study chromosomal radiosensitivity in a population of radiation workers and investigate the possibility of an adaptive response in lymphocytes of workers after short-term occupational exposure to ionizing radiation.


METHODS
The studied group comprised 41 workers temporarily employed at the Nuclear Power Plant Doel (Belgium) for reactor maintenance. A blood sample was taken before and directly after the exposure period of about 1 month. Chromosomal radiosensitivity was assessed in vitro by the G2 assay and the G0 micronucleus (MN) assay. For the MN assay, a low dose-rate (LDR) in vitro irradiation protocol was applied in addition to high dose-rate (HDR) irradiation of the blood samples in order to determine the dose-rate sparing (DRS) effect.


RESULTS
No statistically significant effect of the occupational exposures (up to 10 mSv) on the baseline MN frequencies without in vitro irradiation was observed. A comparison of the number of chromatid aberrations pre- and post-exposure shows no effect of the occupational exposure. On the other hand, the G0-MN assay with the LDR irradiation protocol reveals a systematic reduction in chromosomal radiosensitivity by the exposure, increasing with dose. For workers who received the highest dose (4-10 mSv) a statistically significant (p <0.05) decrease of the in vitro induced MN yields and increase of the dose-rate sparing was observed.


CONCLUSIONS
Short-term low-dose occupational exposure may act as an in vivo adaptive dose and stimulate repair in G0 lymphocytes.
Thierens
H
H
Department of Anatomy, Embryology, Histology and Medical Physics, Ghent University, Proeftuinstraat 86, Belgium. hubert.thierens@rug.ac.be
Vral
A
A
Barbé
M
M
Meijlaers
M
M
Baeyens
A
A
Ridder
L De
LD
D000293:Adolescent; D000328:Adult; D002875:Chromosomes / Q000528:radiation effects* / Q000648:ultrastructure*; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D015162:Micronucleus Tests; D008875:Middle Aged; D009152:Mutagenicity Tests; D016273:Occupational Exposure / Q000009:adverse effects*; D011210:Power Plants; D011829:Radiation Dosage; D013997:Time Factors