摘要Background Lower fluence of 585-nm flashlamp-pumped pulsed dye laser has been successfully used as a nonablative technique in the treatment of wrinkles. The objective of this study was to evaluate the effect of the pulsed dye laser (585 nm) on the production of collagen and the mRNA expression of collagen related gene in fibroblasts in vitro.Methods Cultured fibroblasts were treated with a 585-nm flashlamp-pumped pulsed dye laser ( fluence 3 J/cm2,4 J/cm2, spot size 7 mm, pulse duration 450 μs). The production of collagen and the mRNA expression of transforming growth factor (TGF)-β1, SMAD2, SMAD3, SMAD4, SMAD7 and type I procollagen α1, α2 in fibroblasts were investigated by colorimetry or real time polymerase chain reaction.Results The production of collagen was significantly up-regulated after treatment with a 585-nm flashlamp-pumped pulsed dye laser with a fluence of 3 J/cm2 (P ＜0.001). The mRNA expression of TGF- β1,SMAD2, SMAD3, SMAD4, SMAD7 and procollagen I was significantly up-regulated after treatment with a 585-nm flashlamp-pumped pulsed dye laser with a fluence of 3 J/cm2 (P ＜0.001). No significant difference of mRNA expression of SMAD2, SMAD3, SMAD4, SMAD7 and type I procollagen was found between controls and fibroblasts treated with pulsed dye laser with a fluence of 4 J/cm2 (P ＞0.05).Conclusions Lower fluence (3 J/cm2) pulsed dye laser increased the collagen production in fibroblasts by up-regulating TGF-β1, SMAD2, SMAD3, SMAD4, SMAD7 and type I procollagen mRNA expression. These may be the reason it can be effectively used in the treatment of wrinkles.