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Type I collagen production stimulation of water-filtered near-infrared shown through gene expression changes in a 3-dimensional human epidermal tissue model
Yohei Tanaka, M.D.,Ph.D.
Clinica Tanaka Plastic, Reconstructive Surgery and Anti-aging Center, , Nagano, Japan ;
Results:
A DNA microarray with over 50,000 different probes showed 18 genes that were up- or down-regulated by at least 2-fold after irradiation. Quantitative real-time PCR revealed that, relative to control cells, the gene encoding La ribonucleoprotein domain family member 6 (LARP6), which regulates collagen expression, was significantly up-regulated after 5 and 10 rounds of NIR irradiation at 10 J ⁄cm2 compared to the control (p < 0.05). Statistically significant changes between 5 and 10 rounds were also observed (p < 0.05).
Since LARP6 coordinates the efficient translation of COL1A1 and COL1A2 and COL1A1 plays an important role in type I collagen production, I also performed quantitative real-time PCR analysis of COL1A1, which was significantly up-regulated after 5 and 10 rounds of NIR irradiation at 10 J ⁄cm2 relative to untreated control cells (p < 0.05), and there was no statistically significant difference seen between 5 and 10 rounds of exposure (p = ), as shown in Figure 2.
Conclusion: This study provides an objective assessment of gene expression changes induced by water-filtered broad-spectrum near-infrared, and demonstrates its ability to stimulate type I collagen production, which is beneficial for skin rejuvenation applications.
Background: Water-filtered broad-spectrum near-infrared (NIR) treatment can provide safe, consistent, and long-term effects for skin rejuvenation, as my previous clinical, histological, and biochemical investigations showed. However, there are few studies that examined changes in gene expression induced.
Materials and Methods:
NIR treatment. Near-infrared device emits broad spectrum nm near-infrared together with a water-filter that excludes wavelengths nm (Titan; Cutera, Brisbane, CA, USA) was used, as shown in Figure 1.
Epidermal Model. A commercially available multilayered 3-dimensional cultured human epidermal tissue culture model (LabCyte EPI-MODEL, Japan Tissue Engineering Corporation, Aichi, Japan) was used as an in vitro model of epidermal tissue.
Methods: DNA microarray and quantitative real-time PCR analysis was used to assess gene expression levels. Primers for LARP6, COL1A1, and GAPDH are shown in Table 1.
Figure 1. NIR treatment for 3-dimensional cultured human epidermal tissue model.
Probe Name
Gene Name
Systematic Name
Forward primer
Reverse primer
A_23_P117782
LARP6
NM_018357
GCAAGTAGCTAAGCCTATAGC
CTTGACAGGTAACATCGATTTGG
A_33_P
COL1A1
NM_000088
TGGGAGGAAGCAAAAGACTC
GGGTCATTTCCACATGCTTT
A_23_P13899
GAPDH
NM_002046
ACCTGCCGTCTAGAAAAACCTG
GTGTCGCTGTTGAAGTCAGAGG
Figure 2. Quantitative real-time PCR validation of LARP6 and COL1A1expression.
Fold-change in expression was calculated by setting the median value of expression seen in the control to 1.0. Data are shown as the mean ± SEM. (n=3) *p < 0.05.
Table 1. LARP6, COL1A1, and GAPDH primers used for quantitative real-time PCR analysis.