Comparison of Thermal Damage and Wound Repair in Rat Skin after Bipolar Fractional Radiofrequency and CO₂ Laser Treatment / 대한피부과학회지

ABSTRACT

BACKGROUND: Several studies have described the use of bipolar fractional radiofrequency (FRF) treatment not only to reverse aging or restore photo-damaged skin but also to treat acne and acne-related scarring with a low downtime and few potential complications. However, few histological studies have been conducted to identify the precise mechanism responsible for the success of bipolar FRF treatment. OBJECTIVE: To compare thermal tissue damage and wound repair after exposure to bipolar FRF and ablative CO₂ laser treatment. METHODS: We irradiated the skin of an albino rat (Sprague-Dawley, 200∼250 g) using a CO₂ laser and a bipolar FRF device. Biopsy specimens of the irradiated skin were collected on the first, third and fourteenth day after treatment. For histological analysis, the skin samples were stained with hematoxylin and eosin, Masson's trichrome, and Verhoeff-van Gieson stain. RESULTS: Immediately after bipolar FRF treatment, the skin samples showed coagulated columns in the dermis forming a pyramidal zone of sublative thermal injury. Three days after treatment, they showed re-epithelialization with minimal crust formation. Compared to the ablative CO₂ laser, bipolar FRF treatment showed lower epidermal disruption and more extensive dermal remodeling, with a rapid tissue repair response to the damage. CONCLUSION: With bipolar FRF treatment, wound repair is rapid with minimal recovery time and pigmentary complications. The bulk impact of coagulation and residual heating occurring deep within the dermis causes significant collagen contracture and remodeling, leading to effective improvement in skin texture and wrinkles, acne scars, and dyschromia in all skin types.