Radiation damage in mouse embryos exposed to 1 rad X-rays or negative pions

Abstract

Pregnant mice of two different strains (F/A and NMRI) were exposed to 1 rad of whole-body pion- or X-irradiation at day 8 of gestation. Lucanthone (Miracil D), a known radiosensitizer in various biological systems, was applicated 30 min before irradiation. Five days after treatment the fetuses were observed for developmental anomalies. In both strains of mice it was found that the radiation dose as low as 1 rad results in a significant increase in the rate of abnormal fetuses compared to nonirradiated, but restrained fetuses. Comparing the effectiveness of negative pions (peak irradiation) with X-rays for teratogenic effects, the RBE was between 1.7 and 1.9. The application of Lucanthone increased the number of damaged fetuses and led to various degrees of sensitization depending on the mouse strain and dosage used. Differences between the strains as regards the frequency of damages are explained by different development stages at the time of treatment.

Combined application of misonidazole and piotron pions on mouse embryos

“…The data presented here show a RBE value of 1.6 at 50% malformation which is in good agreement with our previous results of peak pions from the single beam [2]. In contrast to our former data with 1 rad, qualitatively different teratogenic effects between X-rays and pions were observed at higher doses.…”

“…Our previous studies with mouse embryos showed that low level exposures, even to 1 rad, may have a significant deleterious influence on prenatal development [2]. Moreover, potentiating effects with different chemicals and drugs could be demonstrated in the embryonic system of rats and mice.…”

Low-dose or low-dose-rate ionizing radiation–induced bioeffects in animal models

“…Prenatal LDIR exposure induces teratogenesis and mortality [55–61] (Table 5). In female CF1 and BALB/c strain mice, irradiation with X-rays (100 mGy) at 7 h post fertilization resulted in increased frequency of malformed fetuses and Dwarfism occurrence when examined 18 days later.…”

“…When entire oviducts and uteri were examined at 6 and 24 h after irradiation for signs of very early embryos, observations of delayed first cleavage and increase in the number of abnormal embryos were made, suggesting that the newly fertilized egg was probably the most radiosensitive cell in the mouse [63]. Subjecting pregnant mice from two different strains (F/A and NMRI) to 10 mGy of whole-body pion- or X-ray irradiation at Day 8 of gestation resulted in a significant increase in the rate of abnormal fetuses compared with non-irradiated, but restrained fetuses [55]. When pregnant Swiss albino mice were exposed to low doses of X-rays (~9 mGy) on gestational Day 3.5 (pre-implantation period), Day 6.5 (early organogenesis period) or Day 11.5 (late organogenesis period), and the fetuses were examined on the 18th day of gestation, a significant increase in prenatal mortality was observed for those exposed at 3.5 days post coitus (d.p.c.).…”

Chromatid breaks induced in Chinese hamster cells by low doses (12?100 rad) of? ?-mesons

“…We are using this phase for the comparison of the effect from different radiation qualities (Mindek et al, 1975). These investigations are part of the preclinical program including experiments on different biological systems as animals, tissues and cells Michel and Fritz-Niggli, 1977). These investigations are part of the preclinical program including experiments on different biological systems as animals, tissues and cells Michel and Fritz-Niggli, 1977).…”