# Radiofrequency-Induced Thermal Modulation Reduces Senescence-Induced Collagen Fiber Degradation in Facial Ligaments of Animal Models

## TL;DR

Radiofrequency treatment reduces collagen degradation in aging facial ligaments by boosting HSP70 activity and improving collagen structure.

## Contribution

This study reveals a temperature-dependent mechanism of RF in mitigating collagen degradation via HSP70 modulation in senescent facial ligaments.

## Key findings

- RF increased HSP70 expression and HSP70-IKKγ binding, reducing NF-κB activation in senescent fibroblasts.
- RF restored collagen type I/III ratio and fiber density in facial ligaments, with better results at 42 W than 73 W.
- RF improved collagen fiber structure and helical organization in senescent facial ligaments.

## Abstract

What are the main findings?
Radiofrequency (RF) increased HSP70 expression and enhanced HSP70-IKKγ binding, thereby reducing IκBα phosphorylation and NF-κB activation in senescent fibroblasts and facial ligaments.RF restored the collagen type I/III ratio and collagen fiber density in senescent facial ligaments, with more favorable molecular responses observed at 42 W than at 73 W.

Radiofrequency (RF) increased HSP70 expression and enhanced HSP70-IKKγ binding, thereby reducing IκBα phosphorylation and NF-κB activation in senescent fibroblasts and facial ligaments.

RF restored the collagen type I/III ratio and collagen fiber density in senescent facial ligaments, with more favorable molecular responses observed at 42 W than at 73 W.

What are the implications of the main findings?
These findings suggest that HSP70 plays a central role in mediating RF-induced molecular remodeling during ligament senescence.RF provides preclinical evidence of a temperature-dependent mechanism that mitigates collagen degradation and supports extracellular matrix homeostasis in aging connective tissues.

These findings suggest that HSP70 plays a central role in mediating RF-induced molecular remodeling during ligament senescence.

RF provides preclinical evidence of a temperature-dependent mechanism that mitigates collagen degradation and supports extracellular matrix homeostasis in aging connective tissues.

Age-related changes in facial ligaments contribute to altered facial shape and soft tissue descent. Radiofrequency (RF) has been utilized for skin rejuvenation by promoting collagen fiber contraction and synthesis through increased expression of heat shock proteins (HSPs). The primary component of ligamentous collagen fibers undergoes structural modifications with age, exhibiting increased fragmentation and a reduced collagen type I/III ratio. This study aimed to investigate whether RF irradiation alleviates senescence-related changes in facial ligaments through HSP70-mediated molecular remodeling using a UV-induced photoaging rat model. In senescent fibroblasts, RF enhanced the interaction between HSP70 and IκBα kinase (IKK)γ while reducing IκBα phosphorylation, which was associated with decreased nuclear factor-kappa B (NF-κB) activation. These RF-mediated changes were attenuated by an HSP70 inhibitor, suggesting that RF reduces NF-κB activity via HSP70 modulation. RF also suppressed expression levels of matrix metalloproteinases and SMAD7 in senescent fibroblasts. Consistent with in vitro findings, RF increased the interaction between HSP70 and IKKγ while decreasing IκBα phosphorylation and NF-κB activity in the UV-induced photoaging (senescent) facial ligaments of rat models. Furthermore, RF enhanced the collagen type I/III ratio and increased collagen fiber density within the ligaments. Scanning electron microscopy revealed that RF irradiation increased collagen fiber bundle diameter and enhanced the helical structure of those fibers. Overall, RF mitigates senescence-related changes in facial ligaments through HSP70 modulation. Considering that facial ligament laxity contributes to soft tissue descent, facial ligament-targeting approaches may promote a more youthful facial structure. RF demonstrates the possibility in reducing senescence-associated changes within facial ligaments.