Background: Low-level laser therapy (LLLT) continues to receive much attention in many clinical fields. Also, LLLT has been used to enhance the proliferation of various cell lines, including stem cells. This study investigated the effect of LLLT on human adipose-derived stem cells (ADSCs) through in vitro and in vivo studies. Methods: Low-level laser irradiation of cultured ADSCs was performed using a 830 nm Ga–Al–As (gallium–aluminum–arsenide) laser. Then, proliferation of ADSCs was quantified by a cell counting kit-8. In the in vivo study, irradiated ADSCs or non-irradiated ADSCs were transplanted, and then, low-level laser irradiation of each rat was performed as per the protocol. Cell viability was quantified by immunofluorescent staining using the human mitochondria antibody. Results: In the in vitro study, the laser-irradiated groups showed an increase in absorbance compared to the control group. Also, in the in vivo study, there was a significant increase in the number of human ADSCs in the laser-irradiated groups compared to the control group (p < 0.001). Conclusions: Our study showed that LLLT could enhance the proliferation and viability of ADSCs. The ADSCs enhanced by LLLT could be applied in various clinical fields. With the use of LLLT, the proliferation and viability of various cells can be enhanced, besides ADSCs. No Level Assigned: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors http://www.springer.com/00266.
- Gallium–aluminum–arsenide lasers
- Low-level laser therapy
- Stem cells