Radiofrequency treatment induces fibroblast growth factor 2 expression and subsequently promotes neocollagenesis and neoangiogenesis in the skin tissue

Abstract

Radiofrequency (RF) treatment appears to be involved in production of new collagen fibrils and the improvement of existing collagen structures; however, the molecular bases of the effect of non-invasive RF on the skin tissue have not been fully elucidated. This study reports the effects of RF associated or not with hydrolyzed collagen (HC) in the skin tissue. Wistar rats were randomly divided into four groups, according to the treatment received: control group (G1, n = 5), no treatment; subjects in group G2 (n = 5) were treated with HC; and capacitive RF was applied to the back of each subject in G3 (n = 5) and RF associated with HC in G4 (n = 5). Biopsies were taken 30 days after treatment and then were histologically processed and studied for inflammatory cell counting, collagen content, and morphometry. In addition, FGF2, CD105, and COX-2 expression was assessed by immunohistochemical staining. The most relevant changes were the increase in cellularity and accumulation of intercellular substance in RF-treated animals (G3 and G4). The greatest dermis thickness rate was observed in G4, followed by G3 and G2 (p < 0.05). RF-treated skins (G3 and G4) exhibited a significant overexpression of FGF2 (p < 0.0001) and increased microvessel density (p < 0.0001) in comparison with G1 and G2. Moreover, the amount of COX-2 was significantly higher (p < 0.0001) in dermis of RF-treated areas compared to G1 and G2, and demonstrated differences in G3 (RF) compared to G4 (RF + HC) (p < 0.0001). Our results suggests that RF treatment associated or not with HC induces FGF2 overexpression, promotes neoangiogenesis and modulates the COX-2 expression, subsequently promotes neocollagenesis, and increased thickness rate of dermis.

Histological examination of skin tissue in the porcine animal model after simultaneous and consecutive application of monopolar radiofrequency and targeted pressure energy

“…The fat cells shrinkage is believed to be due to accelerated cellular metabolism and hence the release of free fatty acids by the radiofrequency field, 15 and partially due to increased vascularization (discussed below) induced by both RF/ TPE energies. 12,13,19,24 Besides lipolysis, RF and targeted pressure energy are also known to induce neocollagenesis and neoangiogenesis. Meyer and co-authors reported that the application of RF leads to the increased dermal thickness and type I collagen in rats.…”

“…More importantly, the study also showed an increase in the expression of fibroblast growth factor 2 (FGF2), an important signaling protein involved in angiogenesis, and consecutively in the microvessel density. 13 TA B L E 1 Collagen and elastin fiber amount and thickness, dermis thickness, and adipocytes' area. Data expressed as the mean ± standard deviation (SD).…”

“…Various noninvasive technologies such as ultrasound, laser, pressure waves, and radiofrequency (RF) are used to improve the appearance of the skin by inducing effects such as fat lipolysis/reduction, neocollagenesis, neoelastinogenesis, and neoangiogenesis. 2,3,8,9,[12][13][14][15][16][17][18][19] Despite different mechanisms of action, RF-induced heating of dermal and subdermal tissues and pressure energy have similar effects. It was recently reported that monopolar radiofrequency simultaneously applied with targeted pressure energy (TPE) is a viable new method for noninvasive treatment of cellulite and skin laxity in postpubertal women.…”

Advanced fractional radiofrequency for the rejuvenation of face, neck, and décolleté

“…The application of radiofrequency energy to treat skin aging is based on internal thermogenesis induced by applied energy, and it is conventionally considered a nonablative procedure as suggested by Reference 1. As a consequence of such increase in internal temperature, vasodilation and increasing microcirculation occurs, new collagen formation, and contraction of existing collagen fibers 2‐4 . The radial fractional radiofrequency, instead, can be considered ablative by some authors 5 who suggest that it induces coagulation of dermal tissue in columns having the same diameter of the pins of the handpiece, but tissue's parts between the pins remain intact.…”

A simple morphometric analysis method for dermal microstructure using color thresholding and moments

“…In previous research on treatment effects in the dermis, collagen fibers were evaluated and categorized using a scoring system. This system could only be used to show qualitative rather than quantitative improvement . With our method, collagen fiber density can be compared using continuous values and statistical analysis, enabling quantitative assessment of treatment effects.…”