NIR irradiation of human buccal fat pad adipose stem cells and its effect on TRP ion channels.

The effect of near infrared (NIR) laser irradiation on proliferation and osteogenic differentiation of buccal fat pad-derived stem cells and the role of transient receptor potential (TRP) channels was investigated in the current research. After stem cell isolation, a 940 nm laser with 0.1 W, 3 J/cm2 was used in pulsed and continuous mode for irradiation in 3 sessions once every 48 h. The cells were cultured in the following groups: non-osteogenic differentiation medium/primary medium (PM) and osteogenic medium (OM) groups with laser-irradiated (L +), without irradiation (L -), laser treated + Capsazepine inhibitor (L + Cap), and laser treated + Skf96365 inhibitor (L + Skf). Alizarin Red staining and RT-PCR were used to assess osteogenic differentiation and evaluate RUNX2, Osterix, and ALP gene expression levels. The pulsed setting showed the best viability results (P < 0.05) and was used for osteogenic differentiation evaluations. The results of Alizarin red staining were not statistically different between the four groups. Osterix and ALP expression increased in the (L +) group. This upregulation abrogated in the presence of Capsazepine, TRPV1 inhibitor (L + Cap); however, no significant effect was observed with Skf96365 (L + Skf).

Near Infrared Laser Photobiomodulation of Periodontal Ligament Stem Cells.

OBJECTIVE: To determine the effect of different energy densities of near infrared diode lasers with wavelengths of 810 or 940 nm on the proliferation and survival of periodontal ligament derived stem cells (PDLSCs). METHODS: After isolation and characterisation, PDLSCs were cultured in clear 96-well plates. Each well was irradiated by either 810 nm (L1) or 940 nm (L2) lasers, with energy densities of 0.5, 1.5 and 2.5 J/cm2 and an output power of 100 mW. A non-irradiated well was used as a control. Cellular viability was measured 24 hours after irradiation using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and proliferation was measured 24, 48 and 72 hours after irradiation using trypan blue staining and counting. Propidium iodide (PI) staining was used to identify any pyknotic nuclei or nuclear fragmentation 72 hours after irradiation. RESULTS: An increase in viability was observed only in the group with the 940 nm laser irradiation at energy density of 2.5 J/cm2 (P < 0.001). The proliferation of cells was significantly increased in the group with 940 nm laser irradiation at energy density of 2.5 J/cm2 at all the time points examined in comparison to other groups (P < 0.001). PI staining showed no change in cell nuclei in any of the groups. CONCLUSION: Irradiation of PDLSCs with a 940 nm laser at an energy density of 2.5 J/cm2 could promote efficient cell proliferation.

Effect of photobiomodulation with 810 and 940 nm diode lasers on human gingival fibroblasts.

BACKGROUND: The growth and proliferation of gingival fibroblasts are important in the process of oral wound healing, and photobiomodulation (PBM) might be able to modify this process. OBJECTIVES: The aim of the current study was to evaluate the biomodulatory effect of a single session of laser PBM by means of 810 nm and 940 nm diode lasers alone and their combined application with different fluencies on human gingival fibroblasts (HGFs). MATERIAL AND METHODS: Cells were provided by the Pasteur Institute, the National Cell Bank of Iran (NCBI) (C-165). Laser irradiation was carried out using 810 nm, 940 nm and 810 nm + 940 nm in the continuous wave (CW) mode, 100 mW, and energy densities of 0.5, 1.5 and 2.5 J/cm2. Cell viability was evaluated at 24 h with the MTT assay. Trypan blue staining was used to evaluate proliferation 24, 48 and 72 h after laser therapy. Propidium iodine was used to stain DNA and the cell nucleus. RESULTS: Laser irradiation (810 nm, 0.5 J/cm2) increased the viability of gingival fibroblasts, while this dose had an inhibitory effect with 940 nm. No positive effect on cell viability was found with other settings at 24 h. The viability results were not statistically different from those of the control in the dual wavelength group. At all single-laser irradiation doses, the cell proliferation results were lower as compared to the control at 48 and 72 h. The dual wavelength group results were significantly better than those of the control for the 1.5 J/cm2 and 2.5 J/cm2 energy densities (p < 0.001). Propidium iodine staining showed no negative effect of laser irradiation on the cell nucleus in any of the groups. CONCLUSIONS: Although a single irradiation dose of 810 nm, 0.5 J/cm2, resulted in a positive effect on cell viability at 24 h, no statistically significant stimulatory effect on viability and proliferation was observed for the other single wavelength group. When a combination of the 2 wavelengths was used, better results were observed as compared to the control, which needs to be further investigated in future studies.