Relationship between formation of aberrant crypts and acute responses of colonic epithelial cells to genotoxic treatment among inbred rat strains

DNA damage such as chemical carcinogen or gamma-rays induces aberrant crypts in the rat colorectum. We demonstrated that formation of aberrant crypts is different among inbred rat strains (WKAH, DA and F344/N). DA had less preneoplastic lesions in the colorectum than the others regardless of the way of DNA damage. We analyzed changes in in vivo number of colonic epithelial cells undergo mitosis, DNA synthesis and apoptosis following DNA damage histochemically. It is indicated that rapid onset of G1 arrest and termination of G2/M arrest and apoptosis in damaged epithelial cells is important to reduce subsequent formation of the preneoplastic lesions.