Radiation risk of embryonic death at different stages of sex cells development following acute exposure of male mice to low dose ionizing radiation

Gonads belong to the group of the most radiosensitive organs. Continuously dividing seminiferous epithelium cells are the in radiobiological research. Radiation associated reproductive system damage can reduce fertility and cause embryonic loss. To estimate the effect of low-dose gamma-radiation on spermatogenesis, comprehensive quantitative and functional analysis of spermatogenic cells of BALB/c mice exposed to 0.1, 0.25, 0.5 and 1.0 Gy gamma-radiation (137Cs, dose rate 0.85 Gy/min) was performed. To count spermatogenic cells in testes, cellular suspension and epididymal spermatozoids, the Goryaev chamber was used. Functional status of sex cells was assessed by their viability. After exposure to gamma-radiation the number of spermatogenic cells and their viability reduced. Stimulation of proliferative activity, hormesis, was observed in cellular culture exposed to 0.1 and 0.25 Gy. Radiation effects manifested themselves as fertility decline and intrauterine fetal death. The paper presents data on embryonic losses at different stages of spermatogenesis. Antenatal survival decline in animals exposed to 0.1 Gy occurred at the premeiotic stage, in animals exposed to 1.0 Gy - at the postmeiotic stage. Embryonic mortality is caused by intrauterine fetal death occurred prior to the implantation. Postimplantation fetal death reliably exceeds the control level if the animals were exposed to only 1.0 Gy. The study results give evidence that 0.1 Gy is the whole body radiation dose that causes gonadal damage in mice.