Low-Level Laser Irradiation Modulated Viability of Normal and Tumor Human Lymphocytes In Vitro

Low-level laser therapy with different irradiation methods modulated the response of bone marrow mesenchymal stem cells in vitro

Low-level laser therapy (LLLT) also known as photobiomodulation is a treatment to change cellular biological activity. The exact effects of LLLT remain unclear due to the different irradiation protocols. The purpose of this study was to investigate the effects of LLLT by three different irradiation methods on the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) in vitro. BMSCs were inoculated in 24-well plates and then irradiated or not (control) with a laser using three different irradiation methods. The irradiation methods were spot irradiation, covering irradiation, and scanning irradiation according to different spot areas (0.07 cm² or 1.96 cm²) and irradiation areas (0.35 cm² or 1.96 cm²), respectively. The laser was applied three times at energy densities of 4 J/cm². The cell proliferation by CCK-8. ALP activity assay, alizarin red, and quantitative real-time polymerase chain reaction (RT-PCR) were performed to assess osteogenic differentiation and mineralization. Increases in cell proliferation was obvious following irradiation, especially for covering irradiation. The ALP activity was significantly increased in irradiated groups compared with non-irradiated control. The level of mineralization was obviously improved following irradiation, particularly for covering irradiation. RT-PCR detected significantly higher expression of ALP, OPN, OCN, and RUNX-2 in the group covering than in the others, and control is the lowest. The presented results indicate that the biostimulative effects of LLLT on BMSCs was influenced by t he irradiation method, and the covering irradiation is more favorable method to promote the proliferation and osteogenic differentiation of BMSCs.

Light-emitting diode photomodulation of uterine adenocarcinoma cells inhibited angiogenesis capacity via the regulation of exosome biogenesis

This study was conducted to investigate the inhibitory effects of light-emitting diodes (LEDs) on exosome biogenesis and angiogenesis capacity in Ishikawa endometrial cancer cells. To this end, cells were exposed to different energy densities (fluences) of 4, 8, 16, 32, and 64 J/cm² for 5 days (once every 24 h), and cell viability was determined using an MTT assay. Based on data from the MTT panel, cells were exposed to 4 and 16 J/cm² for subsequent analyses. Exosome biogenesis was also monitored via monitoring the expression of CD63, ALIX, and Rab27a and b. The size and morphology of exosomes in the supernatant were measured using scanning electron microscopy (SEM), and dynamic light scattering (DLS). Using Transwell insert, the migration capacity of these cells was studied. The angiogenic effects of irradiated Ishikawa cell secretome at different fluences were monitored on human endothelial cells using in vitro tubulogenesis. Results indicated LED can reduce the viability of Ishikawa cells in a dose-dependent manner. According to our data, 4 and 64 J/cm² groups exhibited minimum and maximum cytotoxic effects compared to the control cells. Data revealed a close proportional relationship between the power of laser and exosome average size compared to the non-treated control cells (p < 0.05). Real-time PCR analysis showed the suppression of Rab27b and up-regulation of Rab27a in irradiated cells exposed to 4 and 16 J/cm² (p < 0.05). These effects were evident in the 16 J/cm² group. Likewise, LED can inhibit the migration of Ishikawa cells in a dose-dependent manner (p < 0.05). Tubulogenesis activity of endothelial cells was suppressed after incubation with the secretome of irradiated Ishikawa cells (p < 0.05). These data showed tumoricidal properties of LED irradiation on human adenocarcinoma Ishikawa cells via the inhibition of exosome biogenesis and suppression of angiogenesis capacity.

Photobiomodulation Therapy Affects the Elastic Modulus, Cytoskeletal Rearrangement and Migration Capability of Human Osteosarcoma Cells

Photobiomodulation (PBM) therapy utilizes low-power lasers to modulate the viability of living human cells and leads to changes in proliferation, differentiation, adhesion and gene expression, even though the rearrangement of cytoskeleton was not previously studied. The present study aims to evaluate the photobiological effects on the elastic behavior of human osteosarcoma cells (MG-63) and their morphological changes. Fluorescence staining, confocal imaging and atomic force microscopy (AFM) topography were performed to study the effects of PBM therapy with the exposure of 532 nm-25mW, 650 nm-3mW, 650 nm-150mW and 780 nm-70mW beams following the 5-min continuous irradiation. The area of each beam was 3.14cm² with a source-surface distance of 20 cm. Besides the cell proliferation assessment, the migratory potential of MG-63 was determined with the wound healing technique. The results indicated an increase in stiffness and shape index of radiation-induced cells 24 h after exposure along with the obvious F-actins changes. But, cell stiffening was not observed 72 h after 532 nm laser irradiation. Also, a decrease in the migration rate was seen in all of the groups after 72 h of irradiation except cells treated with 532 nm wavelength. However, 532 nm laser beams increase the migratory potential 24 h after exposure. Within 72 h after irradiation, the cell proliferation was only affected by applying 532 nm and 650 nm-150mW laser beams. It was concluded that applying photobiomodulation with wavelengths of 650 nm (at both utilized powers) and 780 nm alters the migration capability and provides a quantitative description of cytoskeletal changes. Moreover, membrane stiffening can be considered as the biological marker of PBM treatments.

Dosage Effects of an 810 nm Diode Laser on the Proliferation and Growth Factor Expression of Human Gingival Fibroblasts

Introduction: A substantial amount of evidence supports the positive effect of photobiomodulation on the proliferation and differentiation of various cell types. Several laser wavelengths have been used for wound healing improvement, and their actual outcome depends on the settings utilized during irradiation. However, the heterogeneous wavelengths and laser settings applied in the existing literature make it difficult to draw solid conclusions and comparison of different studies. The aim of the present study is to evaluate and compare the effects of various doses of laser energy, provided by an 810 nm diode, on human gingival fibroblasts in terms of proliferation and expression of growth factors with a pivotal role in wound healing. Methods: Human gingival fibroblasts were cultured on plastic tissue culture and irradiated with 2, 4, 6 or 12 J/cm². The effects of the low-level laser therapy (LLLT) using an 810 nm diode laser on growth factor expression (EGF, TGF and VEGF) were evaluated by qPCR at 72 hours and 7 days after irradiation. Cell proliferation was evaluated at 24, 48 and 72 hours after LLLT using MTT assay. Results: Energy density of 12 J/cm² provoked irradiated gingival fibroblasts to demonstrate significantly higher proliferation as well as higher gene expression of Col1, VEGF and EGF. LLLT positive effects were obvious up to 7 days post-irradiation. Conclusion: LLLT with 810 nm presents beneficial effects on proliferation, collagen production and growth factor expression in human gingival fibroblast cells. The application of 12 J/cm² can be suggested as the optimal energy density for the enhancement of the wound healing process.