[Effects of He-Ne laser irradiation on fibroblasts derived from scar tissue of rat palatal mucosa].

This study was carried out to clarify the mechanism of stimulating effects of low power He-Ne laser irradiation on wound healing process of rat palatal mucosa. Experimental wounds were made in 8-week-old male SD rats by surgically excising mucoperiosteum in hard palate. Fibroblasts were cultured from the scar tissue one month after the excision. Cells were investigated ultrascopically and the effects of He-Ne laser irradiation were examined by measuring DNA and collagen synthesis. Thermal change of the medium was also monitored. Cultured cells from the palatal wounds exhibited features of myofibroblasts. They exhibited well-developed bundles of microfilaments in the cytoplasm and had nuclei with foldings. Single irradiation of He-Ne laser at 28J/cm2 stimulated uptake of [3H] Thymidine into myofibroblasts and the stimulating effect decreased time dependently. There was no significant change in collagen synthesis. No thermal change was detected during irradiation. Ultrascopically, dilatation of rER was observed immediately after irradiation at 28J/cm2. But there was no modification in other cytoplasmic structures. The author concludes that He-Ne laser irradiation stimulates DNA synthesis of myofibroblasts without any degenerative changes in the organelle.