Abstract
Although many clinical studies have tested usefulness of low power laser (LPL) irradiation for the wound healing, the mechanism of the effects by LPL irradiation has not been fully elucidated. The present study demonstrated that the enhanced LPL irradiation effect to the procollagen production was consistently observed in the serum-starved medium, not in the FCS-contained medium. These results suggested that some factors in FCS might interfere with LPL irradiation onto procollagen synthesis. This view is supported by the fact that LPL irradiation was much more effective in intractable ulcers and bloodless wounds, which could be lack in FCS. The LPL irradiation effect was not blocked by dexamethasone but methylene blue. It seems probable that the LPL enhanced effects to the procollagen product of the fibroblast might be occurred at the translational level not at the pretranslational level of the mRNA synthesis and cGMP might be involved in the enhanced effect of the procollagen synthesis in fibroblast.
In vivo study, the effect of the low power laser on the inflammatory stage of wound healing was investigated using delayed wound healing animal model. Round open wounds were made on the bilateral backs of doxorubicin treated pigs. Five-days LPL irradiation (for 3 min/day) suppressed the excess production of fibronectin caused by doxorubicin and also suppressed the number of the infiltrated inflammatory cells. Effectiveness of the LPL was also observed to keratinization. These results suggest that LPL may have immunosuppressive effect and also stimulate on delayed wound healing.
