Effect of photobiomodulation on viability and proliferation of stem cells from exfoliated deciduous teeth under different nutritional conditions

Abstract

This study aimed to evaluate the effect of different doses of low-level laser irradiation on the viability and proliferation of stem cells from exfoliated deciduous teeth (SHED) cultured under nutritional deficit (cellular stress) or regular nutritional conditions. SHED underwent irradiation by a red laser between 1.2 and 6.2 J cm −2 . Prior to the irradiation, all groups received culture medium (MEMα, Eagle's minimum essential medium alpha modification) supplemented with 1% of fetal bovine serum (FBS) for 1 h. After the irradiation, cells received MEMα supplemented with 10% of FBS (regular nutrition) or 1% of FBS (nutritional deficit). Cell viability and proliferation were respectively determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and crystal violet assays 6 and 24 h after irradiation (P < 0.05). At 24 h, SHED under nutritional deficit showed lower viability and proliferation after 1.2 J cm −2 irradiation. All of the irradiated groups revealed significantly higher viability and proliferation in SHED maintained under nutritional deficit than in regular nutritional conditions, except in the 3.7 and 6.2 J cm −2 groups by MTT assay. In the crystal violet assay, SHED irradiated with 1.2 J cm −2 showed no difference between the different nutritional conditions. Decrease of FBS concentration in the culture medium seems to enhance the sensitivity of SHED to the effects of photobiomodulation therapy. Nutritional stress conditions improved cell viability and proliferation of SHED after laser irradiation, except for 1.2 J cm −2 .

The effects of different 650 nm laser diode irradiation times on the viability and proliferation of human periodontal ligament fibroblast cells

“…19 Furthermore, the viability of hPDLF cells indicated their number living in a culture medium, where viability after irradiation with a 570 nm low-level laser was observed at six hours and 24 hours. 13 Low-level laser therapy (LLLT) on stem cells from human exfoliated deciduous teeth (SHED) at a wavelength of 660nm generated the highest cell viability 24 hours after irradiation. On the other hand, the proliferation of hPDLF cells indicated the number of such cells that grow and divide in a culture medium.…”

“…A previous study stated that laser light plays a role in increasing fibroblast proliferation. 13 Furthermore, the wavelength of red light emitting diodes (LEDs) light is 600-700 nm. The wavelength of laser therapy is known to have an influence on cell culture, with one previous study even stating that wavelengths of 600-700 nm can stimulate an increase in cell proliferation and differentiation.…”

Laser treatment contributes to maintain membrane integrity in stem cells from human exfoliated deciduous teeth (shed) under nutritional deficit

“…Under stress conditions, several cell types seem to be more sensitive to the effects of PBMT, having their regenerative potential further stimulated by this therapy [3]. Therefore, in vitro models have tested the efficacy of PBMT by laser irradiation after nutritional deficit by serum starvation, which induces cellular stress, simulating clinical conditions in which a pH reduction occurs, such as tissue inflammation [3][4][5][6]. However, variations in the protocols of nutritional deficit and the parameters of laser irradiation have hindered the comparison of studies on the effect of PBMT in combination with cellular stress [3][4][5].…”

“…Therefore, dentistry has sought therapeutic alternatives to conventional treatments for the healing of inflamed tissues or the replacement of necrotic pulps [8]. Tissue engineering may offer an alternative to conventional rehabilitative treatment of stomatognathic system structures, by regenerating injured tissues through the differentiation of stem cells into specialized cell lines [6][7][8][9][10][11][12]. Stem cells from exfoliated deciduous teeth (SHED) have high rates of cell proliferation, differentiation, and growth factor secretion [8].…”

“…If properly stimulated, SHED are able to differentiate into odontoblasts and endothelial cells [7][8][9][10][11][12], representing useful candidates for dental tissue regeneration. Although mesenchymal cells from various sources have been subjected to laser irradiation to stimulate their regenerative potential [8][9][10][11][12], the effect of PBMT on SHED has been poorly studied [6,10,12,13]. In particular, the assessment of SHED viability after laser irradiation under different culture conditions has been limited [6].…”