Objective. To study the effects of radiation on female fertility.
Design. Experimental study of ovarian follicles radiosensitivity in a murine model.
Setting. University Laboratory.
Animals. NMRI and C57Bl6 mice.
Interventions. To analyse ovarian follicle radiosensitivity, total body irradiation was
performed on 8 days post-partum (dpp) mice with a single exposure to various doses
(0.02; 0.1; 0.5; 2; 8 Gy) and type of radiation (X and ). We assessed fertility of
irradiated (2 Gy) and sham treated mice by scoring pups after mating.
Main outcome measures. Radiation effects were assessed by quantification of
oocytes using histology, immunostaining and 3D approaches in ovaries of irradiated
and sham treated mice. Fertility assessment was performed by counting the number
of pups per mice and reporting the fetal abortion rate.
Results. Primordial follicles (PF) were highly radiosensitive compared to growing
follicles (GF) with a total loss observed from 0.5 Gy and onwards. We calculated a
DL50 for PF equal to 47 mGy and 38 mGy for and X-rays respectively. We show that
PF oocytes are sensitive to radiation doses at least over 80 fold lower than doses killing
GF (0.1 versus 8 Gy). Radiation exposure with 2 Gy induced the same quantity of DNA
damage in both follicle populations. Surviving oocytes from GF were able to complete
folliculogenesis similarly as sham treated mice. After mating, both the non-irradiated
and the irradiated females sired a first litter. However, the rate of early fetal abortion
was about 3 times higher in irradiated mothers compared to the non-irradiated ones.
No more pups were obtained from irradiated females from further mating as the ovarian
reserve was depleted in response to radiation.
Conclusions. Both X and gamma radiations drastically reduced fertility lifespan and
altered the quality of pregnancies. Our results emphasize the need for fertility
preservation before radiation exposure and call for reassessing the use cryopreserved
oocytes.