Chapter 19 Low-Level Laser (Light) Therapy in Tendon Healing in <i>in Vitro</i> and <i>in Vivo</i> Models

Adult stem cells are found in many tissues and organs such asbrain, blood, bone, skin, lung, and liver, where they stay in a specialstructure called “stem cell niche.” They remain quiescent undernormal conditions and become activated when there is a need torepair injury or maintain tissue. Stem cells are very promising inregenerative medicine to treat injury and disease. However, whenisolated and cultured in vitro, stem cells have limited capacity to divide, which makes it difficult to grow large quantities of stemcells for medical application. Low-level laser therapy (LLLT) hasbeen demonstrated to stimulate the proliferation of many kindsof cultured cells, including stem cells. The augmentation of stem-cell-based therapies to modulate regenerative process through LLLTholds great potential. The mechanisms of action, the effects of LLLTon stem cells, and the potential applications of LLLT on stem-cell-based treatment are discussed in this chapter.