Cell Migration Following Irradiation of the Skin in Mice: Effect of shielding minute areas

In the acute radiation reaction of skin it is well known that a hyperplasia may develop in the irradiated skin along the border of a sharply defined field.It has generally been assumed that the hyperplasia is due to migration of non-irradiated epidermal cells into the irradiated epithelium (GLUCKSMANN 1951, VON ESSEN 1969).Following experiments with shielding of narrow strips of epithelium, migration was questioned by DEVIK (1957), mainly because it would have to occur in the epithelium without loss of cells.Experiments in general pathology have indicated that complete loss of epithelium is a prerequisite for migration of epithelial cells.DEVIK concluded that the cells injured by radiation received some factor, or factors, from the shielded cells of importance to recovery, without specifying whether it might be diffusible substances, or parts of cells.In 1969, BARENDSEN in a discussion on the genesis of malignant cells suggested that irradiated cells with defective genomes might fuse, or that a defective cell might be restored by taking up part of the genetic material from another cell.The present experiments were designed as an attempt to detect the origin of the cells responsible for the border hyperplasia.To provide data for analysis, narrow