HUMAN WOUND REPAIR I. Epidermal Regeneration

A series of linearly incised superficial skin wounds was made on the forearms of young adult male volunteers. Wounds were sampled at several intervals between 3 hr and 21 days after wounding, for study by light and electron microscopy. The light microscopic observations show that regeneration of epidermis in human wounds conforms chronologically to that reported for the epidermis in superficial wound repair in laboratory animals. It is further shown that "ruffling" of cell membranes characterizes the cells of the migrating epidermis in early wound healing. This study reveals that the basement lamina and hemidesmosomes are established by epidermis in contact with the fibrin net at the base of early wounds. Epidermal cells in the wound environment are shown to be phagocytic. Analysis of the submicroscopic cytology of differentiating and maturing regenerated epidermis reveals that, in the sequence of events, the formation of filaments, basal lamina, and desmosomes is followed chronologically by evolution of keratohyalin granules and, subsequently, by keratinization of the surface epidermal elements. The entire sequence of migration, differentiation, and ultimate keratinization in the superficial wounds studied requires 3-5 days for completion.