Effects of the lower energy and pulse stacking in carbon dioxide laser skin treatment: an objective analysis using second harmonic generation

Abstract

To evaluate the effect of fractional carbon dioxide (CO 2 ) laser treatment using lower power associated with pulse stacking within collagen fibers, using second harmonic generation microscopy and computerized image analysis. Methods: Twenty male Wistar rats aging eight weeks were used. Each treatment area received a single-pass CO 2 fractional laser with different parameters. The 20 animals were divided into two groups and euthanized after 30 and 60 days. Second harmonic generation images were obtained and program ImageJ was utilized to evaluate the collagen organization within all areas. Collagen anisotropy, entropy and optical density were quantified. Results: Increased anisotropy over time was observed in all four areas, but only reached statistical significance (p = 0.0305) when the mildest parameters were used (area four). Entropy decreased over time in all areas, but without significance (p = 0.1779) in area four. Density showed an overtime increase only in area four, but no statistical significance was reached (p = 0.6534). Conclusion: When combined, the results obtained in this study regarding anisotropy, entropy and density tend to demonstrate that it is possible to achieve collagen remodeling with the use of lower power levels associated with stacked pulses.

Ultrapulse Fractional CO2 Laser With Different Fluences and Densities in the Prevention of Periorbital Laceration Scars: A Split-Scar, Evaluator-Blinded Study

“…Yuan et al 5 observed that there is no significant difference in clinical efficacy between 10 and 20 mJ laser irradiation. Motta et al 6 evaluated the effects of CO 2 laser application on rats at 3 different fluencies and observed no statistically significant difference between 3 different CO 2 fluences in ablation depth, coagulation depth, microscopic thermal zone density, or diameter. These results were compatible with our study, we found no statistically significant difference between high fluences with low density versus low fluences with low-density parameters of UFCL in early scar intervention.…”

“…Laser resurfacing offers plastic surgeons an option for reducing the appearance of posttraumatic hypertrophic periorbital scars. In recent years, intervention with laser devices has been suggested as a novel modality to improve scar formation, 2–8 especially fractional CO 2 laser, which is one of the most effective treatment options used to resurface scars.…”

“…Several studies have evaluated the efficacy of fractional laser treatment of postoperative scars during the early posttraumatic period, but standardized parameters for scar management have yet to be established. Some authors believe that higher parameters correspond to greater laser penetration in the dermis and better clinical results, whereas some authors have advocated choosing low-level laser therapy 4–6 . This randomized controlled trial is the first split-scar comparison study using the ultrapulse fractional CO 2 laser (UFCL) with different parameters.…”

Implanted hair-follicle-associated pluripotent (HAP) stem cells differentiating to keratinocytes, macrophages and endothelial cells accelerated cutaneous wound closure and suppressed scar formation in a mouse model

“…In the thin: thick ratio of epithelial thickness, 1 HPF in one section per a mouse was randomly selected and measured. Quantitative analysis of dermal collagen in Masson's trichrome histological sections was performed using ImageJ software as previously described [21]. In the analysis of dermal collagen, 1 HPF in one section per mouse was randomly selected and quanti ed.…”