title: Red light of 647 nm enhances osteogenic differentiation in mesenchymal stem cells.
abstract: The use of light for medical treatment has been studied previously. In this study, we examined the effect of light from a red light-emitting diode on osteogenic differentiation of mouse mesenchymal stem cells (D1 cells) which were cultured in the presence of osteogenic differentiation medium (ODM) for 3 days, then exposed to a red light-emitting diode (LED) light of 647 nm wavelength once for 10 s, 30 s or 90 s with radiation energies of 0.093 J, 0.279 J and 0.836 J, respectively. D1 cells in the presence of ODM differentiated into osteoblasts, and this process was enhanced on exposure to LED light in ODM medium. This effect was confirmed by increased Alizarin red staining, higher alkaline phosphatase (ALP) activity, higher mRNA expressions of osteocalcin, collagen type I, osteopontin and Runt-related transcription factor2 (Runx2), and higher levels by reverse transcriptase-polymerase chain reaction (RT-PCR) and by increased immunofluorescence staining against cluster of differentiation 44 (CD44) by immunofluorescence microscopy, confocal microscopy and flow cytometric analysis. These data suggest that osteogenic differentiation of mesenchymal stem cells (MSCs) in ODM is enhanced by LED light exposure.
authors.affiliation: Department Orthopaedics, Chonnam National University Hwasun Hospital, 160 Ilsimri, Hwasun-eup, Hwasun-gun, Jeonnam, South Korea.
authors.forename: Hyung Keun
authors.initials: HK
authors.lastname: Kim
authors.forename: Ji Hyun
authors.initials: JH
authors.lastname: Kim
authors.forename: Azlina Amir
authors.initials: AA
authors.lastname: Abbas
authors.forename: Dong-Ok
authors.initials: DO
authors.lastname: Kim
authors.forename: Sung-Jun
authors.initials: SJ
authors.lastname: Park
authors.forename: Jae Yoon
authors.initials: JY
authors.lastname: Chung
authors.forename: Eun Kyoo
authors.initials: EK
authors.lastname: Song
authors.forename: Taek Rim
authors.initials: TR
authors.lastname: Yoon
mesh_terms: D000818:Animals; D002113:Calcification, Physiologic / Q000528:radiation effects; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000528:radiation effects*; D054023:Lasers, Semiconductor; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000528:radiation effects*; D051379:Mice; D010006:Osteoblasts / Q000166:cytology / Q000528:radiation effects*; D010012:Osteogenesis / Q000528:radiation effects; D010789:Phototherapy