Epithelial Mediated Wound Contraction in Experimental Wounds—The Purse-string Effect

Abstract

Wound contraction, a process whereby wound edges are drawn together, is thought to be mediated by the [murine] myofibroblast cell population. Experimental wounds may close as much as 25% (surface area) before the onset of fibroplasia which is marked by the migration of fibroblasts and myofibroblasts into the wound bed 2-3 days after injury. This early phase of wound closure appears to be mediated by a contractile force produced by a circumferentially arranged band of fusiform-shaped epidermal cells situated in the wound margin. Cytoplasmic microfilaments in the epidermal cells, similar in size and configuration to actin filaments and/or tonofilaments, are found to be aligned with the long axis of the constitutive cells comprising the contractile band. Contraction in experimental wounds is promoted by a least 2 distinct cell-mediated contractile events; an initial although brief phase effected by cells of the epidermis followed by an extended phase of soft connective tissue contraction produced vis a vis the myofibroblasts in the dermis.