Male-mediated developmental toxicity in mice after 8 weeks'exposure to low doses of X-rays.

Purpose: The aim of the study was to investigate the effects of subchronic irradiation of male mice on reproduction ability and induction of male-mediated teratogenesis.

Materials And Methods: Male mice were irradiated to 0.05 Gy, 0.10 Gy and 0.20 Gy daily for 8 weeks, 5 days per week. The total doses were 2.00 Gy, 4.00 Gy and 8.00 Gy, respectively. After the end of exposure each male was caged with two untreated females. The females were sacrificed on day 17 based on the finding of a vaginal plug. Females were examined for the number of live and dead implantations and the incidence of congenital malformations of survival foetuses.

Results: The fertilization ability of males was not diminished. The exposure to 0.20 Gy daily significantly decreased the percent of pregnant females and the number of total implantations. Exposure to 0.10 Gy and 0.20 Gy daily caused decreases in the number of live foetuses and induced dominant lethal mutations (over 50% at the highest dose). Exposure to each dose significantly enhanced the number of deaths (especially early) implants. The incidence of gross and skeletal malformations was not statistically significant, except for skeletal malformations at the highest dose.

Conclusions: Results confirmed that irradiation of male germ cells cause genetic effects which could be transmitted to the offspring. After subchronic exposure to low doses the majority of mutations caused premature death. Subchronic exposure to low doses of X-rays did not induce external and skeletal malformations of surviving foetuses.