Lectinhistochemical study of cell surface alterations in mouse embryos exposed to low radiation doses.

The peroxidase-coupled Dolichos biflorus agglutinin (DBA) served as a marker for cell surface alterations in embryonic mouse tissues exposed to low-dose radiation during the early organogenesis (day 9 post conception). In unirradiated embryos, DBA bound selectively to various organ primordia, depending on their differentiation state. The auditory vesicles and the developing blood vessels were the only tissues staining strongly with the lectin. The vascular endothelia also showed the highest radiosensitivity, expressed by the maximal reaction already at 12.5 cGy. Marked surface changes as well were registered in the basal part of the Rathke's pocket and in the roof of the diencephalon. After exposure to 25 cGy, a transient amplification of the reaction as compared with 12.5 cGy occurred firstly in the Rathke's pocket, then in the infundibulum and in auditory vesicles. The most distinct effects were achieved with 50 cGy. Remarkable is the prompt rise of the DBA-affinity in a narrow area of the myelencephalon, and subsequently also in the roof of the diencephalon. Furthermore, the infundibulum and the Rathke's pocket, both anlagen of the pituitary gland, bound heavily DBA during the entire examination period of 24 h. The present study demonstrated the outstanding suitability of the Dolichos biflorus agglutinin for histochemical detection of subtle cellular alterations by small radiation doses.