Altering CO2 Laser Pulse Energy Settings Did Not Influence Differential Gene Transcription in Normal Skin in a Red DurocPig Model.

Abstract

Fractional ablative CO2 lasers are used clinically to treat cutaneous burn scars with reported varying degrees of effectiveness. It was hypothesized that different laser pulse energy settings may lead to differential gene transcription in a porcine model. Uninjured skin from red Duroc pigs was treated with a fractional ablative CO2 laser set to 70, 100, or 120 mJ across the abdomen (n = 4 areas per treatment). Punch biopsies of both treated and untreated sites were taken before treatment (baseline), at 30 min, and at each hour for 6 h and stored in All-Protect tissue reagent. The biopsies were then used to isolate RNA, which was subsequently used in qRT-PCR for eight genes associated with wound healing and the extracellular matrix: CCL2, IL6, FGF2, TIMP1, TIMP3, COL1A2, MMP2, andDCN. RPL13a was used as a housekeeping gene to normalize the eightgenes of interest. One-way ANOVA tests were used to assess for differences among laser pulse energies and two-way ANOVA tests were used to assess the differences between treated and untreated areas. While six of the eight genes were upregulated after treatment (p < 0.05), there were no significant differences in gene expression between the different laser pulse energies for any of the eight genes. While laser treatment is correlated with a positive and significant upregulation for six of the eight genes 4 h after intervention, the pulse energy settings of the laser did not lead to a statistically significant difference in gene transcription among the treatment areas. Different laser pulse energies may not be required to induce similar cellular responses in a clinical setting.