Hamilton B F, Benjamin S A, Angleton G M, Lee A C
Collaborative Radiological Health Laboratory, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins 80523.
Radiat Res. 1989 Aug;119(2):366-79.
Beagle dogs were given single, whole-body 60Co gamma-radiation exposures at one of three prenatal (8, 28, or 55 days postcoitus) or three postnatal (2, 70, or 365 days postpartum) ages to evaluate the relative radiosensitivity of various stages of brain development. A total of 387 dogs received mean doses ranging from 0.16 to 3.83 Gy, and 120 dogs were sham-irradiated. Groups of dogs were sacrificed at preselected times from 70 days to 11 years of age. Brain weight decreased significantly with increasing dose in dogs irradiated at 28 or 55 days postcoitus or at 2 days postpartum. Irradiations at 28 days postcoitus were dramatically more effective in causing a reduction in brain weight than those at 55 days postcoitus or 2 days postpartum. Among dogs given 1.0 Gy or more and followed for up to 4 years, there was a radiation effect evident at all three sensitive exposure ages. Among dogs given lower doses and followed for up to 11 years, there was a significant decrease in brain weight in dogs given 0.80-0.88 Gy at 28 days postcoitus. All decreases in brain weight were present after normalization for radiation-induced reductions in skeletal (body) size. No specific morphologic changes were noted in the brains which showed the radiation-related reductions in size.
比格犬在三个产前年龄（交配后8、28或55天）或三个产后年龄（产后2、70或365天）之一接受单次全身60Coγ射线照射，以评估大脑发育各阶段的相对放射敏感性。共有387只犬接受了0.16至3.83 Gy的平均剂量照射，120只犬接受假照射。在70天至11岁的预先选定时间对犬群实施安乐死。在交配后28或55天或产后2天接受照射的犬，脑重量随剂量增加而显著降低。交配后28天照射导致脑重量减轻的效果比交配后55天或产后2天照射显著得多。在接受1.0 Gy或更高剂量并随访长达4年的犬中，在所有三个敏感照射年龄均出现了辐射效应。在接受较低剂量并随访长达11年的犬中，交配后28天接受0.80 - 0.88 Gy照射的犬脑重量显著降低。脑重量的所有降低均在对辐射引起的骨骼（身体）大小减少进行归一化后出现。在显示出与辐射相关的大小减少的大脑中未观察到特定的形态学变化。
