Increased fibroblast proliferation and activity after applying intense pulsed light 800–1200 nm

Abstract

Background and objectivesLight devices emitting near infrared have been shown to be highly effective for the skin rejuvenation but biochemical and molecular mechanism or optimum dose treatment are not well-known. In our study we try to elucidate why systems emitting near infrared produce skin improvement such as fibroblasts proliferation, increase in gene expression or extracellular matrix (ECM) protein production. Study design/materials and methods1BR3G human skin fibroblasts were used to test the effects of an intense pulsed light device emitting with an 800–1200nm filter (MiniSilk FT manufactured by Deka®). In our protocol, fibroblasts were irradiated twice successively with a 10Hz frequency, with a total fluence up to 60J/cm2 for 15s each pass. After incubating for 48h, fibroblasts were harvested from the culture plates to test cell proliferation by flow cytometer. To determine changes in gene expression (mRNA levels for collagen types I and III and metalloproteinase 1 (MMP-1)) and protein production (hyaluronic acid, versican and decorin) tests were performed after irradiation. ResultsAfter 48h irradiation, 1BR3G human skin fibroblasts were observed to proliferate at a fast rate. The study of ECM macromolecules production using ELISA showed an increase of hyaluronic acid and versican production but no changes were observed for decorin. With RT-PCR assays, an increase in mRNA for collagen type I, type III and MMP-1 were observed. ConclusionIntense pulsed light emitting near infrared applied in vitro cultured cells increases fibroblasts proliferation and activity, which can be a possible mechanism of action for these devices in aging skin treatment.