Effects of Ultra-Pulse CO2 Fractional Laser at Different Energy Levels on Collagen Metabolism in Rabbit Ear Hypertrophic Scars
Objective Investigation of the effects of Ultra-Pulse CO2 fractional laser at different energy levels on collagen metabolism in rabbit ear hypertrophic scars.Methods Four New Zealand healthy white rabbits were used in this study,and a total of 40 hypertrophic scar models were created on the ventral side of their bilateral rabbit ears.The models were randomly divided into four groups:low-energy laser group(30 mJ),medium-energy laser group(50 mJ),high-energy laser group(70 mJ),and scar control group.Each group consisted of 10 scar models.After treating the hypertrophic scars with lasers at different energy levels,the macroscopic changes of the scars in the four groups were observed and recorded.Scar tissues were collected at 1 week and 8 weeks post-treatment for Masson staining to observe collagen deposition and measure the collagen volume fraction.Immunohistochemistry was performed to detect the expression of TGF-β1.Results Based on overall observations,scar tissues treated with low,medium,and high-energy laser groups exhibit varying degrees of color lightening,texture softening,and height reduction.Among them,the high-energy laser group shows the most pronounced effects.Masson's staining reveals that laser treatment with different energy levels significantly reduces collagen content within the scars,whereas the collagen content gradually decreases and stabilizes in the scar control group as the scars mature.Immunohistochemical analysis demonstrates that laser groups with different energy levels exhibit inhibitory effects on the expression of TGF-β1,with statistical Significance(P＜0.05).Among them,the high-energy laser group exhibits the most significant impact,with statistically significant differences(P＜0.05).Conclusion Ultra-pulse CO2 fractional laser intervention effectively modulates scar collagen metabolism.Under the same fractional density,high-energy laser intervention yields better results than low-energy laser intervention.It is speculated that high-energy laser can more effectively downregulate the expression of TGF-β1,thereby improving scar symptoms.
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