Abstract
Low-power lasers have been reported to significantly enhance the healing rate in both soft and hard tissues. The stimulatory action of laser seems to occur during the proliferative stage of healing by stimulation of prostaglandin E2 (PGE2) and cyclooxygenase-2 (COX-2), which are crucial early mediators in the natural healing process. The effect of Er:YAG laser irradiation on PGE2 production and COX-2 gene expression in human gingival fibroblast in vitro were investigated.
Cultured fibroblasts were exposed to low-power Er:YAG laser irradiation with an energy density of 3.37 J/cm2. The amount of PGE2 production was measured by enzyme-linked immunosorbent assay (ELISA). COX-2 mRNA level, which is a critical enzyme for production, was analyzed by reverse transcriptase-polymerase chain reaction(RT-PCR).
Er:YAG laser significantly increased PGE2 production by human gingival fibroblasts. COX-2 mRNA, which was hardly detectable in control, increased dramatically after irradiation. COX-2 inhibitor, NS398, completely inhibited the PGE2 synthesis stimulated by Er:YAG laser irradiation.
Er:YAG laser irradiation appears to exert its stimulative action on gingival fibroblasts proliferation through the production of PGE2 via the expression of COX-2. This should be considered as one of the important regulatory pathways to accelerate wound healing after Er:YAG laser irradiation.
