Effect of Low-Level Laser Therapy on Proliferation and Collagen Synthesis of Human Fibroblasts in Vitro

초록

Background Low-level laser therapy (LLLT) is a nonthermal technology that can be used to modulate cellular activity through light irradiation at specific pulse sequences. in vitro and in vivo studies have been performed previously to determine the effect of LLLT on wound healing. However the results were inconsistent. Final purpose of our project is to determine effect of LLLT on diabetic wound healing and this pilot study was designed to confirm effect of LLLT on activity of healthy human fibroblasts. In particular, we focused on cell proliferation and collagen synthesis, which are main contributing factors in would healing. Methods Healthy human fibroblasts obtained from cryopreserved cells (n=10) were irradiated at wavelength of 635 nm (RED), 830 nm (IR), and 635 nm+830 nm (FX) with the same fluence of 60 J/cm2 , after seeding into 96-well plates. A group in which no laser exposure was applied was assigned as control. Fibroblast proliferation was examined by EZ-Cytox enhanced cell viability assay and immunohistochemistry (IHC). Collagen synthesis was measured by IHC. IHC pictures were analyzed to identify the intensity values of collagen type I as quantity results. Results Irradiation at FX and IR groups showed a significant increase in fibroblast proliferation and collagen synthesis compared to control and RED groups. There was no significant difference in fibroblast proliferation and collagen synthesis between FX group and IR group. Conclusion Healthy human fibroblasts showed better cell proliferation and collagen synthesis when they were irradiated at wavelength of 635 nm+830 nm or 830 nm.

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