Influence of low level laser radiation on migration of stem cells

Abstract

The long term effects of low level laser therapy can involve treatment mechanisms connected with activation of stem cells. In the current study migration of stem cells was tested under the influence of laser light alone as well as in case of combined influence of light and stromal cell-derived factor-1α (SDF-1α). This cytokine plays a role in lymphocyte trafficking, hematopoietic progenitor cell and stem cell homing. To investigate the light influence on stem cells, we analyzed factor-dependent cell-Patersen (FDCP)-mix multipotent progenitor cells. Migration of the stem cell line was tested using Transwell system (Corning, NY) under influence of red diode laser (λ=659.6 nm, 19.5 mW) or infrared diode laser (λ=958 nm, 36 mW) during 15 min at continuous wave, as well as in case of applying 150 ng/ml SDF-1α. Group 1 cells were a group of control, group 2 cells received only red light irradiation, while group 3 cells had IR light irradiation. Group 4 cells were treated with 150 ng/ml SDF-1α. Group 5 cells were irradiated with red laser light in addition to 150 ng/ml SDF-1α, and group 6 cells by IR light and 150 ng/ml SDF-1α. The count of migrated cells was 1496,5±409 (100%) in case of control. Red and IR laser light increased migration activity of stem cells up to 1892±283 (126%) and 2255,5±510 (151%) accordingly. Influence of SDF-1α was more significant, than effects of light irradiation alone 3365,5±489 (225%). Combined effects of light irradiation and SDF-1α were significantly stronger 5813±1199 (388%) for SDF-1α and red laser light, and 6391,5±540 (427%) for SDF-1α and IR laser light irradiation. Preliminary study results showed that laser light irradiation can activate stem cell migration in vitro. The results are more reliable in the case of combined application of light and SDF-1α. These results are giving ground to consider that stem cell reactions to light irradiation can be one of the factors of light therapy.