Expression of growth factor and receptor mRNAs in skin epithelial cells following acute cutaneous injury.

We report that acute injury induces the expression of selective growth factor and growth factor receptors in the epithelial cells of the wounded tissue. In situ hybridization analysis of skin biopsy specimens obtained after cutaneous injury in swine demonstrated the induction of the expression of transforming growth factor-alpha, its receptor, epidermal growth factor-R, acidic fibroblast growth factor, and basic fibroblast growth factor messenger RNAs in the skin epithelial cells of the wounded tissue. There was no significant expression in the epithelial cells of control, uninjured tissues. The expression levels were maximal during the period of active tissue repair (1 to 5 days after injury) and were totally suppressed upon the healing of the wounded tissues. In contrast, insulinlike growth factor-I, (IGF-I), IGF-I receptor, and IGF-II receptor messenger RNAs were expressed in the epithelial cells of both the control, uninjured tissues and in tissue specimens obtained after injury. There was no significant expression of IGF-II messenger RNA in the epithelial cells before or after injury. It seems that injury induces the coordinated expression of selective growth factor and growth factor receptor genes whose products contribute to the regulation of the complex processes involved in tissue repair and remodeling.