Salmon-Derived Polydeoxyribonucleotide: A Potent Marine Bioactive Agent Against Skin Photoaging

The effects of topical salmon-derived polydeoxyribonucleotide (PDRN) against UVB-induced skin photoaging remain incompletely characterized. We investigated the protective effects of 0.25%, 0.5%, and 1% topical PDRN treatment against UVB-induced photoaging in SKH-1 hairless mice, comparing them with 1% L-ascorbic acid (L-AA). Mice were exposed to 0.18 J/cm2 of UVB three times weekly for 15 weeks, with daily topical treatments. Chronic UVB exposure induced severe wrinkles and edema and reduced cutaneous procollagen type I C-peptide levels. However, PDRN treatments significantly and dose-dependently mitigated these changes. Notably, 0.5% PDRN reduced mean wrinkle length and depth by 41.04% and 44.54%, respectively, with responses of similar magnitude to those observed with 1% L-AA. PDRN treatment increased skin hydration and cutaneous procollagen type I C-peptide and hyaluronan levels, accompanied by increased COL1A1/2 and Has1/2/3 mRNA expression. Furthermore, PDRN restored glutathione levels, reduced thiobarbituric acid-reactive substances (TBARS) levels and superoxide anion production, decreased MPO activity and IL-1β levels, and increased IL-10 levels. These changes were accompanied by decreased p38 MAPK, AKT, and Nox2 mRNA expression and increased TGF-β1 mRNA expression. These preclinical findings support further investigation of topical PDRN, including delivery, safety, and efficacy studies.