The effect of low-level laser therapy (660 nm) on the gene expression involved in tissue repair

Abstract

The effect of low-level laser therapy (LLLT) on the healing of skin lesions has been evaluated in many studies; however, the molecular mechanisms involved in the biostimulatory effects resulting from this treatment need to be better understood. The paper aims to analyze the effects of LLLT (660 nm) at doses of 1 and 5 J/cm on cell viability and expression of vascular endothelial growth factor (VEGF) and interleukin (IL6) genes in L929 fibroblast cells. The dose-response curve was performed with the GaInAlAs (660 nm) laser-treated cells at energy rates of 1 and 5 J/cm. Cell viability was quantified at 24, 48, and 72 h after irradiation and the effects of TLBP on the cytoskeleton and endoplasmic reticulum were evaluated by fluorescence microscopy and the RT-qPCR method was used for the analysis of gene expression. It was observed that the 72 h group had a statistically significant increase in cell viability compared to the 48 h group (p < 0.01) and when compared to the 72 h control (p = 0.03). In 72 h, a greater distribution of the cytoskeleton filaments and the more evident endoplasmatic reticulum was verified, indicating an increase in the protein synthesis when compared with the control group. In the expression of the VEGF gene, a significant increase of 1.98 times (p < 0.05) in the number of transcripts was observed; whereas for the IL6 gene, a decrease of the transcripts was 4.05 times (p < 0.05), both occurring within 72 h after irradiation at 5 J/cm. The LLLT (660 nm) at the dose of 5 J/cm should modulate cellular viability, upregulated VEGF, and downregulated IL6 expression of messenger RNA in culture of L929 fibroblast cells.

Light‐emitting diode irradiation using 660 nm promotes human fibroblast HSP90 expression and changes cellular activity and morphology

“…However, considering the other outcomes in current study such as MTT analysis showing the viability of the cells, it is highly probable that these cells are proliferating rather that dying. In line with other reports showing that light energy aided wound‐healing , our results suggest that LEDs exert such an effect.…”

Fatores de crescimento e síntese de proteínas na resposta celular após aplicação do laser de baixa intensidade

“…The methodology of this study was based on previous research [28][29][30]. We used 660 nm wavelength based on the maintenance of HPF viability and proliferation [28] and effect in gene expression [18,21,30]. Before PBM, HPF secreted and produced all the tested angiogenic factors, except for PDGF in lysate, which agrees with the literature [13,[45][46][47][48][49].…”

“…The methodology of the two studies were based on previous research (Lourenço-Neto et al, 2017;Marques et al, 2017;Fernandes et al, 2018). We used 660-nm wavelength based on the maintenance of HPF viability and proliferation (Marques et al, 2017;Fernandes et al, 2018), effect in gene expression (Oliveira et al, 2015;Szezerbaty et al, 2018) and on the assumption that the visible spectrum would have effects on protein synthesis (Alghamdi et al, 2012). The used irradiances ranged from 1.2 to 6.2 J/cm 2 , that is, irradiances shorter than those reported to decrease immortalized oral fibroblast viability (Engel et al, 2016).…”

“…In terms of biomodulation, the higher power and dose upregulated the angiogenic factors (VEGF-A, VEGF-C, FGF-2, BMP-9, and VEGFR1 in supernatant and VEGF-A and VEGF-C in lysate). In general, photobiomodulation of angiogenesis increases VEGF production due to nitric oxide modulation [21,31]. This occurs through nitric oxide production synthase via activation of PLCϒ-Ca dependent influx [32][33][34].…”

“…Works from other fields reveal that photobiomodulation (PBM) modulated the synthesis of angiogenic growth factors by mesenchymal stem cells from adipose tissue [18] and gingival fibroblasts [19,20]. Recently, the literature reports that PBM at 660 nm increase VEGF gene expression in fibroblasts [21], but little is known whether higher gene expression results in higher protein production and secretion.…”