A Low-Level Carbon Dioxide Laser Promotes Fibroblast Proliferation and Migration through Activation of Akt, ERK, and JNK

BACKGROUND: Low-level laser therapy (LLLT) with various types of lasers promotes fibroblast proliferation and migration during the process of wound healing. Although LLLT with a carbon dioxide (CO(2)) laser was also reported to promote wound healing, the underlying mechanisms at the cellular level have not been previously described. Herein, we investigated the effect of LLLT with a CO(2) laser on fibroblast proliferation and migration. MATERIALS AND METHODS: Cultured human dermal fibroblasts were prepared. MTS and cell migration assays were performed with fibroblasts after LLLT with a CO(2) laser at various doses (0.1, 0.5, 1.0, 2.0, or 5.0 J/cm(2)) to observe the effects of LLLT with a CO(2) laser on the proliferation and migration of fibroblasts. The non-irradiated group served as the control. Moreover, western blot analysis was performed using fibroblasts after LLLT with a CO(2) laser to analyze changes in the activities of Akt, extracellular signal-regulated kinase (ERK), and Jun N-terminal kinase (JNK), which are signaling molecules associated with cell proliferation and migration. Finally, the MTS assay, a cell migration assay, and western blot analysis were performed using fibroblasts treated with inhibitors of Akt, ERK, or JNK before LLLT with a CO(2) laser. RESULTS: In MTS and cell migration assays, fibroblast proliferation and migration were promoted after LLLT with a CO(2) laser at 1.0 J/cm(2). Western blot analysis revealed that Akt, ERK, and JNK activities were promoted in fibroblasts after LLLT with a CO(2) laser at 1.0 J/cm(2). Moreover, inhibition of Akt, ERK, or JNK significantly blocked fibroblast proliferation and migration. CONCLUSIONS: These findings suggested that LLLT with a CO(2) laser would accelerate wound healing by promoting the proliferation and migration of fibroblasts. Activation of Akt, ERK, and JNK was essential for CO(2) laser-induced proliferation and migration of fibroblasts.