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

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.