Low-level laser irradiation induces in vitro proliferation of stem cells from human exfoliated deciduous teeth

Abstract

The aim of this study was to evaluate the effect of low-level laser irradiation (LLLI) on the proliferation and viability of stem cells from human exfoliated deciduous teeth (SHED). Cells were irradiated or not (control) with an InGaAlP laser diode (660 nm, 30 mW, continuous action mode) using two different energy densities (0.5 J/cm-16 s; 1.0 J/cm-33 s). Irradiation was performed at 0 and 48 h, with the laser probe fixed at a distance of 0.5 cm from the cells. Cell proliferation was analyzed at 0, 24, 48, and 72 h by the Trypan blue exclusion method and MTT assay. Cell cycle and Ki67 expression were analyzed by flow cytometry. Apoptosis-related events were evaluated by expression of annexin V/PI and nuclear morphological changes by staining with DAPI. Differences between groups at each time were analyzed by the Kruskal-Wallis and Mann-Whitney tests, adopting a level of significance of 5% (p < 0.05). The results showed that an energy density of 1.0 J/cm promoted an increase in cell proliferation at 48 and 72 h compared to the control and 0.5 J/cm groups. Cell cycle analysis revealed a predominance of cells in the S and G2/M phases in the irradiated groups. This finding was confirmed by the increased expression of Ki67. Low positive staining for annexin V and PI was observed in all groups, and no nuclear changes were detected, indicating that cell viability was not affected by the energy densities tested. It can be concluded that the LLLI parameters used (660 nm, 30 mW, 1.0 J/cm) promote the proliferation of SHEDs and the maintenance of cell viability.

Effects of 660 nm and 810 nm Low‐Power Diode Laser on Proliferation and Invasion of Oral Cancer Cells in Cell Culture Media

“…An up‐regulation of the Ki67 marker was observed following laser irradiation (56). Fernanda Ginani et al studied the effects of low‐power lasers on stem cells derived from human deciduous teeth and observed an increase in the expression of the Ki67 marker (57). However, our research shows that no studies have been performed on the effects of these two markers on cancer cells.…”

Effects of low-level laser therapy and adipose-derived stem cells on the viability of autologous fat grafts: a preliminary study

“…Our previous study showed that LLLT enhanced the viability and proliferation of ADSCs both in vitro and in vivo [5]. Other studies have reported positive effects of LLLT on stem cells [24,25].…”

Laser therapy increases the proliferation of preosteoblastic MC3T3‐E1 cells cultured on poly(lactic acid) films

“…MC3T3‐E1 preostoblastic cells (obtained from American Type Culture Collection [ATTC], USA) were cultured in an α‐MEM medium supplemented with 10% FBS and 1% antibiotic and antimycotic (100 IU/ml penicillin, 100 mg/ml streptomycin, and 0.25 μg/ml amphotericin B; all from Gibco, USA) and categorized into three groups: Group I (growth control)—cells cultured on a polystyrene plastic surface; Group II (PLA)—cells cultured on a PLA film and not submitted to laser irradiation; and Group III (PLA + Laser)—cells cultured on a PLA film and submitted to laser therapy. Cells in Group III were subjected to a single irradiation with an InGaAIP diode laser (Kondortech, Brazil) at 660 nm, 30‐mW power, 4.0 J/cm 2 energy density, using a 0.01‐cm 2 tip diameter, in continuous action mode, and plated in such a way that an empty well was present between seeded wells, in order to prevent unintentional light scattering between wells during laser application (Ginani, Soares, de Oliveira Rocha, de Souza, & Barboza, 2018). The irradiation probe was applied perpendicular to the plate at a 0.5‐cm distance from the cells and the PLA film.…”