Influence of laser radiation on migration of stem cells

Abstract

The long-term effects of low level laser therapy can involve mechanisms connected with activation of migration of stem cells towards damaged areas. Stromal cell-derived factor-1 alpha (SDF-1) plays a critical role in stem cell migration towards areas of tissue injury and hypoxia. This study examines the influence of laser light on migration of stem cells (FDCP-mix stem cell line) in absence and in presence of SDF-1, using Transwell system with 2 connected chambers separated by a filter. The first chamber contained medium and stem cells, second chamber contained medium with or without SDF. Group 1 cells served as a control. Cells of groups 2 and 5 were irradiated by red diode laser (660 nm, 20 mW, 15 min). Cells of groups 3 and 6 received infrared (IR) diode laser (958 nm, 36 mW, 15 min). Group 4 was SDF-1 control. Stem cells were seeded into first chamber of the Transwell system, and filters were placed into the wells containing medium with 150 ng/ml SDF-1 (groups 4, 5, 6) or without SDF-1 (groups 1, 2, 3). After incubation cells were collected and counted. The count of spontaneously migrated cells was 1496,5±409 (100%) in case of control. Red and IR laser light increased motility of stem cells up to 1892±283 (126%) and 2255,5±510 (151%) accordingly. Influence of SDF-1 caused directed migration of 3365,5±489 cells (225%). Combined effects of light irradiation and SDF-1 were significantly stronger (p<0,05): 5813±1199 (388%) for SDF-1 and red laser , 6391,5±540 (427%) for SDF-1 and IR laser. Study shows that laser radiation can up-regulate stem cell migration towards higher SDF-1 gradient.