Threshold dose to developing central nerve system of rats and mice from prenatal exposure to tritiated water

Objective: To study the threshold dose to the developing central nerve system of rats and mice from prenatal exposure to tritiated water. methods: Pregnant adult C57BL/6J strain mice and Wistar strain rats were irradiated with beta-rays from HTO by a single intraperitoneal injection on the 12.5 th and 13 th days of gestation. The activities of HTO were 24.09, 48.18 and 144.54 ( x 104 Bq/g bw), respectively. Fifty-six parameters including postnatal growth, neutro-behavior, pathology of brain, neuropeptide contents, changes of hippocampal neurons, Ca2+ conductance of hippocampal neurons etc were used to test the teratogenic threshold dose the lowest dose was different from that of the control). Results: Of the observed 56 parameters of rats and mice 80.4% indicated that the threshold doses for prenatal HTO exposure ranged from 0.030 Gy to 0.092 Gy, and the other 19.6% showed the threshold doses from 0.093 to 0.300 Gy. Conclusions: There exists threshold dose from the low level tritiated water irradiation of the developing central nerve system