The effects of low-level laser irradiation on differentiation and proliferation of human bone marrow mesenchymal stem cells into neurons and osteoblasts—an in vitro study

Abstract

Bone marrow-derived mesenchymal stem cells (BMSCs) are promising for use in regenerative medicine. Several studies have shown that low-level laser irradiation (LLLI) could affect the differentiation and proliferation of MSCs. The aim of this study was to examine the influence of LLLI at different energy densities on BMSCs differentiation into neuron and osteoblast. Human BMSCs were cultured and induced to differentiate to either neuron or osteoblast in the absence or presence of LLLI. Gallium aluminum arsenide (GaAlAs) laser irradiation (810 nm) was applied at days 1, 3, and 5 of differentiation process at energy densities of 3 or 6 J/cm(2) for BMSCs being induced to neurons, and 2 or 4 J/cm(2) for BMSCs being induced to osteoblasts. BMSCs proliferation was evaluated by MTT assay on the seventh day of differentiation. BMSCs differentiation to neurons was assessed by immunocytochemical analysis of neuron-specific enolase on the seventh day of differentiation. BMSCs differentiation to osteoblast was tested on the second, fifth, seventh, and tenth day of differentiation via analysis of alkaline phosphatase (ALP) activity. LLLI promoted BMSCs proliferation significantly at all energy densities except for 6 J/cm(2) in comparison to control groups on the seventh day of differentiation. LLLI at energy densities of 3 and 6 J/cm(2) dramatically facilitated the differentiation of BMSCs into neurons (p < 0.001). Also, ALP activity was significantly enhanced in irradiated BMSCs differentiated to osteoblast on the second, fifth, seventh, and tenth day of differentiation (p < 0.001 except for the second day). Using LLLI at 810 nm wavelength enhances BMSCs differentiation into neuron and osteoblast in the range of 2-6 J/cm(2), and at the same time increases BMSCs proliferation (except for 6 J/cm(2)). The effect of LLLI on differentiation and proliferation of BMSCs is dose-dependent. Considering these findings, LLLI could improve current in vitro methods of differentiating BMSCs prior to transplantation.

Effects of low-level laser therapy on the expression of osteogenic genes during the initial stages of bone healing in rats: a microarray analysis

“…LLLT has been shown to have various biostimulatory effects, such as increase cell proliferation and accelerate tissue metabolism [12,21,22]. In this context, several studies demonstrated that LLLT had a positive effect in the process of bone consolidation in experimental models in rats [9,23,24].…”

Transplantation of mononuclear cells from bone marrow in a rat model of Huntington&rsquo;s disease

“…It might be tempting to postulate that this population consists of neurons derived from phenotypically modified mBMCs. Such transformation has been reported in vitro, 21,22 but new experiments will be required to answer this question in our in vivo model. In similarly lesioned and transplanted animals, we were able to show that transplanted cells apparently survive for a long time.…”

“…28 The object recognition paradigms have been reported to be affected by striatal lesions in rats. 21 Our results show that QA striatal lesion reduces the exploring behavior and the identification of the novel object in the object recognition test. Transplanted animals explore significantly more and show a preference for the exploration of the novel object, suggesting a recovery of memory and visual recognition; however, the question of whether this is the result of the presence of replacement cells or an unspecific effect of injection emerges after the improvement shown by DMEM-treated animals in this test.…”

Effect of Diode Laser on Healing of Tooth Extraction Socket: An Experimental Study in Rabbits

“…Some studies focused on osteoblastic differentiation using LLLT. The results of three studies showed that LLLT was effective in the stimulation of osteoblasts differentiation [31][32][33]. On the other hand Bouvet-Gerbettaz et al [34] and Coombe et al [35] showed no beneficial effect of laser on the proliferation and differentiation of osteoblasts.…”