EFFECT OF PHOTOBIOMODULATION ON THE PROLIFERATION OF STEM CELLS FROM HUMAN EXFOLIATED DECIDUOUS TEETH CULTURED ON POLYLACTIC ACID FILMS

Abstract

<h3>Backgorund</h3> Photobiomodulation stimulates the proliferation of different cell types, including stem cells. Stem cells from human exfoliated deciduous teeth (SHEDs) present a greater differentiation potential compared to other mesenchymal stem cells, being the focus of several studies in the field of tissue engineering. In order for cells to proliferate and differentiate in vitro it is necessary to develop a favorable microenvironment, which can be provided by a biomaterial that mimics the natural extracellular matrix, with polylactic acid (PLA) being distinguished for this purpose due to its properties of biocompatibility and biodegradability, as well as low cost. The aim of this study was to evaluate the effect of PBM in different doses on the proliferation and viability of SHEDs cultured on PLA scaffolds. <h3>Methods</h3> SHEDs were isolated, characterized and then cultured on the films and divided into three groups: (C) non-irradiated control; (L1) irradiated with a dose of 1 J/cm²; and (L4) irradiated with a dose of 4 J/cm². The irradiations were performed with an InGaAlP diode laser, with wavelength of 660 nm and power of 30 mW, in a single dose. Cell viability and proliferation were evaluated at 24, 48 and 72 h after irradiation by Alamar Blue assay and cell cycle events were analyzed by flow cytometry at 72 hours. Cell morphology and their distribution on the surface of the films were evaluated by scanning electronic microscopy (SEM) at 72 hours. <h3>Results</h3> Data from Alamar Blue assay showed that groups L1 and L4 exhibited greater cell proliferation compared to group C, with significant differences between L1 and C at 48 and 72 h (<i>p</i><0.0001) and between L4 and C in 24 (<i>p</i><0.01), 48 (<i>p</i><0.001) and 72 h (<i>p</i><0.0001). The percentage of reduction of Alamar blue was significantly higher in L4 compared to L1 at 24 and 72 h (<i>p</i><0.05). The irradiated groups (L1 and L4). presented a higher percentage of cells in the proliferative cell cycle phases (S and G2/M). Analysis of the samples by SEM showed that in the irradiated groups the cells had a more homogeneous distribution on the surface of the films and a higher cell density compared to the group C, with this difference being even more evident in the L4 group. <h3>Conclusion</h3> We conclude that PBM in the studied parameters, especially with the dose of 4 J/cm², stimulates the proliferation of SHEDs in contact with PLA films, suggesting that this protocol can be potentially applied in dental tissue engineering.