Scanning electron microscopic and immunocytochemical studies of contraction during secondary CO2 laser wound healing in rat tongue mucosa.

An experimental model was established in which the decrease in surface area of CO2 laser wounds on rat tongues was measured during the healing process. Scanning electron microscopy was used to measure and delineate the outlines of the initial wounds and those of the residual wounds. A 50% decrease in the surface area of the wounds was observed 10 days after surgery during the healing process. At day 30, the scar surface area was less than 10% (7.4%) of the wound surface area at day 2. This contrasts with studies reported elsewhere where only minimal contraction was observed during the healing of CO2 laser wounds. Immunoperoxidase techniques revealed that three different phenotypes of myofibroblasts were present inside the healing area, expressing vimentin, actin and desmin. These persisted until day 30 after CO2 irradiation.