Therapeutic Anti-Fibrotic Effects of a Dual Hyaluronic Acid Hybrid Complex in Bleomycin-Induced Dermal Fibrosis and UVB-Irradiated Human Skin

Cutaneous fibrosis is characterized by aberrant wound healing with excessive extracellular matrix deposition, sustained inflammation, and oxidative stress, while currently available therapies show limited efficacy and safety. A Dual Hyaluronic Acid Compound (DHC), consisting of high-molecular-weight, low-molecular-weight, and minimally cross-linked hyaluronic acid, has demonstrated regenerative and antioxidant properties, but its anti-fibrotic effects have not been fully explored. This study investigated the anti-fibrotic potential of DHC using a bleomycin-induced murine dermal fibrosis model and a UVB-irradiated ex vivo human skin model. In C57BL/6 mice, dermal fibrosis was induced by daily bleomycin injections for three weeks, followed by intradermal DHC administration. Histological and biomechanical analyses showed that DHC significantly reduced dermal thickness, collagen deposition, and skin hardness compared with untreated fibrotic controls. DHC decreased α-SMA expression and increased MMP1 levels, indicating attenuation of myofibroblast activation and enhanced matrix remodeling. It also reduced macrophage markers (CD68, CD163) and pro-inflammatory cytokines (IL-1β, TNF-α). Furthermore, DHC restored superoxide dismutase (SOD) and catalase (CAT) activity and upregulated NRF2, HO-1, and NQO1 expression in the in vivo model. Similarly, DHC upregulated SOD and CAT activity and reduced pro-inflammatory cytokines (IL-6, TNF-α) in the ex vivo human skin model. These findings suggest that DHC exerts multimodal anti-fibrotic effects through coordinated regulation of fibroblast activation, inflammation, and oxidative stress, supporting its potential as a therapeutic approach for cutaneous fibrosis.