Low Level Laser Irradiation Effects on Proliferation and Apoptosis in Bone Marrow Mesenchymal Stem Cells

Low level laser irradiationis an effective method in treating some diseases and it could improve regeneration and wound healing. Some studies have reported that low level laser irradiation could enhance proliferation by increasing ATP level in the cells mitochondria.Mesenchymal stem cells (MSCs) are a kind of stem cells which are capable of differentiating to other cells. Nowadays, MSCs are an appropriate option for regenerative medicine. In this study we want to investigate the optimum protocol for using low level laser irradiation to improve proliferation and make less apoptosis in Mesenchymal stem cells. The Mesenchymal stem cells were isolated from femur and tibia of a male rat and cultured in culture media. The isolated cells were differentiated to adipocyte and osteocyte to confirm their multi potency. The cells were irradiated with different exposure protocols of 808 nm diode laser. After exposure the stem cells markers (CD90, CD44 and CD45), doubling time, colony forming frequency and Caspase 3 activity (for apoptosis evaluation) were assessed.Both 640 mW (8th group) and 830 mW (14th group) have best result in colony forming and doubling time; however the 8th group had the least Caspase 3 activity. The patterns of stem cells markers expression have not changed after laser irradiation.The protocol used in 8th group could improve Mesenchymal stem cells proliferation more than the rest protocols and also it might make the apoptosis less than the other group. This irradiation protocol could be useful in regenerative medicine due to its effects on Mesenchymal stem cells