effect of gamma irradiation on the developing medulla oblongata of the chick embryo

ABSTRACT

The morphological and histological changes following one integral dose [100 rads] of gamma rays of the developing medulla oblongata were evaluated in chick embryos. The study was carried out on 120 eggs [40 control and 80 irradiated]. Half of the embryos [control and irradiated] were sacrificed on the 12th day of incubation and the other half on the 16th day. Histopathological examination of the irradiated embryos in both ages showed evidence of retardation of growth in the form of reduction in the size of the medulla of 12 days irradiated embryo with changes in the shape of the fourth ventricle. Also, there was reduction in the size of some nuclei with decrease in the cell density. Other nuclei were ill defined with necrotic neuroblastic cells and shrinked neuroglial cells in between. In 16 days irradiated embryos the medulla increased in size. Some nuclei became dispersed, irregular in shape and hardly seen. Also, the neuroblastic and the neuroglial cells were surrounded by clear cavitation [edema]. Moreover, there were gliosis [fibrosis] and edema in between the neuroblastic cells of both ages. These changes resulted in loss of the cytoarchitectural pattern of the irradiated medulla oblongata. The present results were compared to those of previously published investigations