Biostimulation” Effects on hBM-MSCs Proliferation for Tissue Engineering Application

Introduction Over the last year, the role of physical factors, as well as biochemical factors, in modulating and reprogramming cell functions has been highlighted [1]. Low-level laser therapy (LLLT), also known as BIOSTIMULATION, is an emerging therapeutic approach in which cells or tissue are exposed to low-levels of red and near-IR light from lasers. Although the underlying mechanism of LLLT are not yet completely understood several demonstrated that that it can prevent cell apoptosis and improve cell proliferation, migration, and adhesion in many cell types [2]. To date, the combination of LLLT and stem cells is a quiet novel scientific research and its helpful application in tissue engineering is still debate. LLLT may be an alternative method to modulate MSC behaviours. In this study the in vitro effect of LLLT on proliferation of MSCs isolated from adult human bone marrow, hBM-MSCs was investigated. Materials and Methods Cells were exposed at different laser energy doses (0,5-2-5 J/cm2, AlGaInP semiconductor, output power 130 mW at 659 nm) and irradiation protocol (single or irradiation for three consecutive days). The first irradiation day was set as day 0. Cell proliferation assay was performed at days 4 and 7 of culturing. For morphology investigation, cells were analyzed by co-immunolocalization of alfa-Tubulin and F-actin using Confocal Laser Scanning microscopy (CLSM). Results Cells viable number significantly increased from day 1 to days 4 and 7 both in single or multiple irradiated group than to not-irradiated control (fig. 1). Moreover, no differences in the experimental groups were observed (data not shown). Discussion and Conclusions Within the parameters assessed in this study, we demonstrated that LLLI enhances the proliferation potential of hBM-MSCs without inducing morphological damage. Thus, it can be assumed that the power and energy doses used in the present study can be safely employed for irradiation of cells in vitro. Therefore, studies on the LLLT molecular mechanism as well as on its best and safely exposure regime may be important in term of its tissue engineering applications.