Myofibroblasts in healing laser wounds of rat tongue mucosa.

The distribution of myofibroblasts was studied in healing laser incisions compared with scalpel-incision and excision wounds in dorsal tongue mucosa and excision wounds in back skin. Myofibroblasts (m-f-b) were visualized by staining with NBD-phallacidin, a fluorescent probe specific for F-actin, and by electron microscopy. Few, randomly-orientated m-f-b were found in laser wounds over 28 days. Neither m-f-b nor contraction were seen in the scalpel-incisions. No contraction was observed in the laser wounds whereas an organized network of m-f-b with substantial contraction occurred in excision wounds. It is suggested that lack of contraction in laser wounds is partially due to the fewness of m-f-b. The residual connective tissue matrix resisting the laser treatment also seems to play a role in preventing the wound contraction.