Ultra‐Pulsed Fractional <scp> CO ₂ </scp> Laser Combined With Stromal Vascular Fraction Gel: Synergistic Effects and Underlying Mechanisms in Depressed Scars

ABSTRACT Objective To investigate the therapeutic efficacy and underlying molecular mechanisms of stromal vascular fraction gel (SVF‐gel) combined with ultra‐pulsed fractional CO 2 laser (UFCL) in the treatment of depressed scars. Methods A rat model of depressed scars was established by full‐thickness excision of dorsal skin. After two months of intervention, scar repair was evaluated using gross observation, hematoxylin–eosin (HE) staining, and Masson's trichrome staining. The levels of tumor necrosis factor‐α (TNF‐α) and interleukin‐6 (IL‐6) were detected by enzyme‐linked immunosorbent assay (ELISA) and Western blot. The expression of fibrosis‐related molecules, including transforming growth factor‐beta 1 (TGF‐β1), alpha‐smooth muscle actin (α‐SMA), type I collagen (Col‐I), type III collagen (Col‐III), TNF‐α, and IL‐6, was assessed by Western blot and immunohistochemistry. Results Compared with all other groups, the SVF‐gel + UFCL combination group exhibited significantly greater improvement in scar depression and a more pronounced reduction in scar area. Histological analysis showed thicker dermal tissue, more regular collagen fiber arrangement, signs of subcutaneous fat regeneration, and optimized collagen deposition in the combination group. At the molecular level, all treatment groups displayed downregulated expression of TNF‐α and IL‐6, and upregulated expression of TGF‐β1, α‐SMA, Col‐I, and Col‐III, compared with the model group, with the most significant changes observed in the combination group. Conclusion SVF‐gel combined with UFCL exerts a synergistic effect on promoting depressed scar repair by inhibiting chronic inflammation, activating fibroblasts, and promoting collagen synthesis. This study provides a novel synergistic therapeutic strategy for the clinical management of depressed scars.