The effect of low-level laser therapy (660nm) 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 (660nm) at doses of 1 and 5J/cm2 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 (660nm) laser-treated cells at energy rates of 1 and 5J/cm2. Cell viability was quantified at 24, 48, and 72h 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 72h group had a statistically significant increase in cell viability compared to the 48h group (p<0.01) and when compared to the 72h control (p=0.03). In 72h, 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 72h after irradiation at 5J/cm2. The LLLT (660nm) at the dose of 5J/cm2 should modulate cellular viability, upregulated VEGF, and downregulated IL6 expression of messenger RNA in culture of L929 fibroblast cells.