Abstract
The distribution of the extracellular matrix glycoprotein, tenascin, in normal skin and healing skin wounds in rats, has been investigated by immunohistochemistry. In normal skin, tenascin was sparsely distributed, predominantly in association with basement membranes. In wounds, there was a marked increase in the expression of tenascin at the wound edge in all levels of the skin. There was also particularly strong tenascin staining at the dermal-epidermal junction beneath migrating, proliferating epidermis. Tenascin was present throughout the matrix of the granulation tissue, which filled full-thickness wounds, but was not detectable in the scar after wound contraction was complete. The distribution of tenascin was spatially and temporally different from that of fibronectin, and tenascin appeared before laminin beneath migrating epidermis. Tenascin was not entirely codistributed with myofibroblasts, the contractile wound fibroblasts. In EM studies of wounds, tenascin was localized in the basal lamina at the dermal-epidermal junction, as well as in the extracellular matrix of the adjacent dermal stroma, where it was either distributed homogeneously or bound to the surface of collagen fibers. In cultured skin explants, in which epidermis migrated over the cut edge of the dermis, tenascin, but not fibronectin, appeared in the dermis underlying the migrating epithelium. This demonstrates that migrating, proliferating epidermis induces the production of tenascin. The results presented here suggest that tenascin is important in wound healing and is subject to quite different regulatory mechanisms than is fibronectin.
Highlights
The distribution of the extracellular matrix glycoprotein, tenascin, in normal skin and healing skin wounds in rats, has been investigated by immunohistochemistry
The results obtained for fibronectin in normal skin and healing wounds were in agreement with those previously obtained by GrinneU et al (1981)
Tenascin in normal skin was found to be only associated with basement membranes and hair follicle dermal sheaths
Summary
The distribution of the extracellular matrix glycoprotein, tenascin, in normal skin and healing skin wounds in rats, has been investigated by immunohistochemistry. In which epidermis migrated over the cut edge of the dermis, tenascin, but not fibronectin, appeared in the dermis underlying the migrating epithelium. This demonstrates that migrating, proliferating epidermis induces the production of tenascin. Some extracellular matrix molecules (e.g., fibronectin and collagen type III) that are abundant in embryonic skin and less abundant in adult skin, are reexpressed at high levels in healing skin wounds (Kurkinen et al, 1980; review by AIvarez, 1986). Collagen type III is increased in the early granulation tissue and is later replaced by collagen type I These two collagen types impart strength to the healing wound (reviewed by Cohen and McCoy, 1983). Tenascin is absent or expressed at low levels in the adult mammary gland, but is abundant in mammary carcinomas (Mackie et al, 1987a, Inaguma et al, 1988)
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