Morphological analysis of denudation of the villi in the intestinal form of acute radiation sickness

Portions of the duodenum, jejunum, and ileum of sexually mature rats and mice were studied under light and electron microscopes on the third and fourth days after irradiation in doses of 1000, 1500, 7000, and 15,000 R. Denudation of the stroma of individual villi was observed in paraffin sections of the mucous membrane of the small intestine 3–4 days after irradiation. However, examination of thin and semithin Epon sections under the light microscope and of ultrathin sections in the electron microscope showed that the villi always were covered by enterocytes, the cytoplasm of which was loaded with lipid droplets and showed loss of its structural details. In the intestinal form of acute radiation sickness intravital denudation of the villi thus does not take place and its existence in paraffin sections is the result of unsuitable treatment of the material.