The initiation of epidermal wound healing in cuts and burns.

An apparatus to produce shallow linear burns is described. The burns contained about the same amount of damaged tissue as a shallow cut. The initiation of healing in cuts and burns on guinea-pig ears was studied using an 3H-thymidine and autoradiographic technique to determine the number of cells in DNA synthesis in epidermis adjacent to the wound. Cuts caused epidermal cells to enter DNA synthesis rapidly; the maximum response was 1 day after injury. Thus response was delayed in burns and the maximum was not seen until at least 3 days after burning. Extracts of normal skin stimulated epidermal DNA synthesis, whereas extracts of burned skin did not. Possible mechanisms affecting the delay in the healing of burns are discussed.