The 800-nm Diode Laser Irradiation Induces Skin Collagen Synthesis by Stimulating TGF-β/Smad Signaling Pathway

This study investigated the effects of 800-nm diode laser irradiation on skin collagen synthesis using an animal model with eight 2-month-old rats. The laser treatments at 20, 40, and 60 J/cm² significantly improved the histological structure and increased dermal thickness compared to non-irradiated controls. Notably, irradiation at 40 J/cm² significantly up-regulated the expression of procollagen types I and IV, TGF-β, and Smad2, 3, 4, with enhanced levels of p-Smad2 and p-Smad3. The findings suggested that the 800-nm laser effectively improved skin structure and induced new collagen synthesis through the TGF-β/Smad signaling pathway, indicating its potential use for non-ablative skin rejuvenation.