Comparison of Moderate and High Energy of a Nano-Fractional Radiofrequency Treatment on a Photoaging Hairless Mice Model

Background Fractional radiofrequency (FRF) has been widely used in skin rejuvenation. To explore optimal settings, it is important to compare different treatment parameters. Objective This study was designed to compare the effect of moderate-energy and high-energy FRF treatment on a hairless mice model. Methods Fifteen photoaged hairless mice were assigned to 3 groups: control, moderate energy, and high energy. Two treatment sessions (T × 1 and T × 2) were performed at 1-month interval. Transepidermal water loss was measured at baseline, immediately, 1, 2, and 4 weeks after T × 1. Skin samples were harvested before each treatment, 1 and 2 months after T × 2. Neocollagenesis was evaluated by hematoxylin and eosin staining, Masson staining, and immunohistochemistry analysis. Results Transepidermal water loss of high-energy group was significantly higher than the moderate-energy group (p = .008) immediately after T × 1. Remarkable fibroblast proliferation was observed at 1 month after T × 1, followed by significant dermal thickening, and increase of Type I collagen and Type III collagen. There was no significant difference between 2 energy groups in fibroblast proliferation, dermal thickness, and collagen density. Conclusion The effect of moderate-energy treatment was comparable with that of high energy in neocollagenesis, whereas moderate energy yielded less damage to skin barrier function.