Radiation Injury to the Canine Thymus Lymphohematopoietic Stem Cells - Correlation with Functional Deficits

摘要

Immunologic and hematopoietic responses were studied in dogs following prenatal or neonatal irradiation to evaluate the effects of ionizing radiation on the developing lymphohematopoietic system. Pregnant beagle dams received abdominal Co-60 gamma radiation exposures (200 R) or sham-irradiations at 35 days of gestation. Offspring from a second group of dams received 173 R whole-body gamma radiation or sham-irradiation at 10 days of age. The mean calculated dose to each fetus or neonate was 1.5 Gray. These data show that prenatally or neonatally-irradiated dogs have significant postnatal immunologic and hematopoietic defects. The observation of altered lymphocyte subpopulations suggests altered immunoregulation and raises some important questions relating to radiation-induced immunodeficiency and increased susceptibility to clinical disease, including neoplasia. Keywords: Radiation; Immune responses; Thymus; Bone marrow.