SYNCHRONOUS APPEARANCE OF FIBRONECTIN, INTEGRIN ALPHA-5-BETA-1, VINCULIN AND ACTIN IN EPITHELIAL-CELLS AND FIBROBLASTS DURING RAT TRACHEAL WOUND-HEALING

The distribution of integrin alpha 5 beta 1 (alpha 5 beta 1) and assoc iated components during wound healing was investigated in the rat trac hea following mechanical injury. Under anesthesia, the ventral surface of the trachea was scratched, and tissue specimens were obtained from 6 h to 3 weeks after injury and studied using light and electron micr oscopy and immunohistochemistry. alpha 5 beta 1, vinculin and actin in regenerating epithelial cells and extracellular fibronectin appear vi rtually simultaneously after injury (from 12 h to 7 days) as do alpha 5 beta 1, vinculin and a-smooth muscle actin in fibroblasts and cellul ar fibronectin in granulation tissue (from 3 to 10 days). Immunoelectr on microscopy 2 days after injury showed that alpha 5 beta 1 and vincu lin were localized on the basal and lateral surfaces of regenerating e pithelial cells and fibroblast surfaces, and fibronectin was localized just under the regenerating epithelial cells, around collagen fibrils and sporadically around fibroblasts. Bromodeoxyuridine labeling showe d that the appearance of these components was associated with the peri od of cell proliferation. The appearances of fibronectin, alpha 5 beta 1, vinculin and actin in regenerating epithelial cells and fibroblast s during tracheal wound healing are well coordinated. During the initi al cell migration phase, plasma fibronectin may stimulate cell migrati on before cellular fibronectin is produced in situ, and regenerating e pithelial cells appear to begin to migrate into the wound before cell proliferation starts.