Postirradiation Regeneration of Intestinal Epithelium in W/W^v and Sl/Sl^d Genetically Anemic Mice

Not all rapidly proliferating tissues of the mouse are adversely affected by action of mutant alleles at the W- and Sl loci. In contrast to greatly impeded proliferation of blood-cell precursors, primordial germ cells, and melanocyte precursors in W/W^v and Sl/Sl^d anemic, sterile, black-eyed white mice, normal proliferation of intestinal mucosa was observed in mice of these same genotypes. Determinations of number of cells per intestinal crypt, labeling index, mitotic index, and uptake of tritiated thymidine per mg of mucosa, showed no significant differences between values for untreated normal (+/+) and anemic (W/W^v and Sl/Sl^d mice. The intestinal mucosa of the W/W^v and Sl/Sl^d mice responded to radiation insult in the same manner as did that of +/+ mice. Mice of all three genotypes were equally able to increase proliferative activity in the crypts, and to restore normal cell numbers. Differences between these findings and other recent studies are discussed.