The role of contractile proteins in wound healing and fibrocontractive diseases.

During the healing of an open wound, the majority of granulation tissue fibroblasts (myofibroblasts) acquire morphological, biochemical, pharmacological, and immunological characteristics typical of contractile cells. The presence of contractile proteins and the appearance of gap junctions between several myofibroblasts make them similar to cultivated fibroblasts; these have been proven to develop in vitro a contractile force similar to that exerted by granulation tissue during wound contraction. These observations suggest that myofibroblasts are responsible for granulation tissue contraction. Epidermal cells moving over an open wound also develop a contractile apparatus and many cellular connections in the form of gap junctions. These changes may be the morphological support for epithelial cell movements. The presence of gap junctions between myofibroblasts and healing epidermal cells shows that granulation tissue contraction and epithelial cell movement are probably synchronized rather than individual phenomena.