Cell migration following irradiation of the skin in mice. Effect of shielding minute areas.

In hairless mice, dorsal skin flaps were exposed to 15 kV roentgen radiation. Thin metal wires were stretched across the field. At eight different intervals, up to 6 days, and following Colcemid injection, the number and location of mitoses in the epidermis were recorded. The regeneration observed in the irradiated parts of the epidermis seems to be due to migration of cells from shielded areas, the rate during the first 6 days being about 1/6 mm per day. Migration takes place along the basal membrane of the epidermis before any increased loss of cells in superficial layers has occurred.