Experimental comparative study of the effect of fractional CO₂ laser combined with pulsed dye laser versus each laser alone on the treatment of hypertrophic scar of rabbit ears

Abstract

Background and Objective The use of fractional CO2 laser and pulsed dye laser (PDL) therapy to treat and/or prevent scarring following burn injury is becoming more widespread with a number of studies reporting reduction in scar erythema and pruritus following treatment with lasers. The objective of this study was to directly compare the efficacy of PDL, fractional CO2, and PDL and fractional CO2 laser therapy in immature red hypertrophic scars in a standardized animal model. Methods Ten New Zealand big‐eared rabbits were used to make rabbit ear hypertrophic scar models. A total of 80 hypertrophic scar models were obtained and randomly divided into groups: control (Group A), Fractional CO2 laser (Group B), pulse dye laser (Group C), combined (Group D), 20 in each group. Wound sites were treated with PDL, Fractional CO2 laser, or both at 28 days post‐grafting. Grafts receiving no laser therapy served as controls. Hypertrophic scar appearance, morphology, size, and erythema were assessed, and punch biopsies were collected. At days 7 and 28, additional tissue was collected for biomechanical analyses and markers for HE staining, Masson staining, immunohistochemical method to determine the CD31 content in the scar; Western blot to detect the expression of VEGF protein in scars. After the day 7 and 28, the scars were collected. Histomorphological change in scars was observed by hematoxylin‐eosin staining, Masson staining. The expression of CD31, VEGF protein, and the cell apoptosis rate was detected by immunohistochemical method. Results (i) In morphological observation, HE staining and Masson staining, both the number of fibroblasts and amount of collagen fibrils in the experimental group were significantly reduced compared with those in control group. (ii) Micro‐vessel Density (MVD) value can be found much smaller in the experimental groups than the control (p < 0.05). Among the four experimental groups, there was a significant difference among 14d, 21d, and 28d groups (p < 0.05). (iii) On days 7 and 28 after treatment, expression of VEGF could be regulated in experimental group (p < 0.05). Among the three experimental groups, the decrease of VEGF in the combined group was significantly stronger than that of the other two. Conclusion The effect of Fractional CO2 laser combined with pulsed dye laser treatment was shown to be better than that of Fractional CO2 laser or pulsed dye laser alone and inhibits the early hypertrophic scar in rabbit ears.

Efficacy of pulsed dye laser combined with fractional CO2 laser in the treatment of pediatric burn scars

“…In another study, the PDL and fractional CO 2 lasers were equally effective in the treatment of hypertrophic scars 11 . In the experimental study, the authors found that VEGF expression in the composited laser group was weaker than that in the PDL group and fractional CO 2 group at 7 days, 14 days, and 28 days after treatment, with significant differences between the groups 37,39 . Fractional CO 2 laser can increase the apoptosis of fibroblasts, promote collagen degradation, and reduce the secretion of VEGF by epidermal cells, so as to inhibit the proliferation of microvessels and promote the maturation and vascular regression of hypertrophic scar 40–42 .…”

“…36 Chen et al demonstrated that the combination of PDL and fractional CO 2 laser could improve the treatment effect on red hypertrophic scars, partly by regulating the expression of vascular endothelial growth factor (VEGF), through morphological observation and histological experiments. 37 Zhang et al demonstrated that the combination of 595-nm PDL and fractional CO 2 laser could better improve the scar condition over mono-application, partly through the inhibition of expression of proliferating cell nuclear antigen and transforming growth factor-β1. 38 In another study, the PDL and fractional CO 2 lasers were equally effective in the treatment of hypertrophic scars.…”

“…11 In the experimental study, the authors found that VEGF expression in the composited laser group was weaker than that in the PDL group and fractional CO 2 group at 7 days, 14 days, and 28 days after treatment, with significant differences between the groups. 37,39 Fractional CO 2 laser can increase the apoptosis of fibroblasts, promote collagen degradation, and reduce the secretion of VEGF by epidermal cells, so as to inhibit the proliferation of microvessels and promote the maturation and vascular regression of hypertrophic scar. [40][41][42] In our previous studies, we also demonstrated that PDL combined with fractional CO 2 laser could effectively treat fresh red hypertrophic scars in adults with no severe side effects.…”

Clinical efficacy of ablative laser combined with pulsed dye laser in the treatment of pathological scars: A systematic review and meta‐analysis

“…This caused a change in the shape and histology of the rabbit model's hypertrophic scar. Chen, H. Y 45 . discovered that the effect of a dot matrix CO2 laser paired with a pulsed dye laser inhibited early hypertrophic fibrosis in rabbit ears better than either the dot matrix CO2 laser or the pulsed dye laser individually.…”

Advances in Photoelectric Therapy for the Early Intervention and Treatment of Traumatic Scars

“…A prospective, randomized control trial found in comparison to control and CO 2 laser alone, treatment with a combination of IPL and fractional CO 2 laser showed greater average improvements in both texture and color across the majority of examined scar domains, indicating by employing a variety of wavelengths to target the different chromophores in scars, a multi-photo-thermolytic approach combining IPL with CO 2 AFL could be successful in treating hypertrophic scars. 57 However, Laura et al looked at hypertrophic burn scars of different ages, origins, and thicknesses. Although greater early decrease is seen in thicker scars when utilizing CO 2 , PDL, or both laser modalities, there was no clinically significant advantage discovered comparing combined therapy to individual therapy.…”