The process of skin healing in experimentally wounded carp

Abstract

The process of skin healing was studied in thin sections of adult mirror‐carp, superficially wounded with a razor blade in a scaleless region. Shortly after wounding, epidermal cells from both sides of the wound moved towards the wound cavity. The cells moved as compact groups, without severing the normal intercellular desmosomes. The moving cells displayed phagocytotic activity of cellular debris during the migration. The phagosomes reacted with diaminobenzidine, revealing strong peroxidase content. The normally abundant pinocytotic vesicles from the basal layer of filament cells vanished during the first hour after wounding, and reappeared after 2 days; 24 h after wounding, desmosomes interconnected the filament cells from both sides of the wound. Due to profuse mucus secretion, the number of mucous cells from the epidermal stratum was markedly reduced. Rodlet cells appeared 1 h after wounding in the external region of the epidermis. There was pronounced increase in alkaline phosphatase content of the pavement cells 10 min after wounding; this enzyme appeared around the ridges of the pavement cells and inside the mucous cells 20 min later.In the dermis, the region surrounding the wound was darkened, blood cells extravasated, and penetrated partially into the epidermis. After 2 days, dermal fibroblasts displayed intense phagocytosis; after 8 days they were particularly abundant in the region of regenerating tissue and were secreting large quantities of collagen. Marked changes in the relative frequency of the different types of leucocyte occurred during the post‐wounding days.