Anti-inflammatory and antioxidant succinyl-chitosan oligosaccharide protects human epidermal cell and mouse skin against ultraviolet B-induced photodamage.

Ultraviolet B (UVB) irradiation from sunlight is one of the primary environmental factors that causes photodamage to the skin. The aim of this study was to prepare succinyl-chitosan oligosaccharide (SU-COS) and evaluate its protective effects and related molecular mechanisms against UVB-induced photodamage for the first time. SU-COS (substitution degree: 69.26 %, molecular weight: 6400 Da) was shown to have excellent biocompatibility and to effectively promote the migration of human epidermal HaCaT cells. UVB irradiation was used to develop photodamage models in HaCaT cells and murine skin. In vitro, treatment with SU-COS significantly increased the cell survival ratio by >11 % while concurrently reducing reactive oxygen species formation, preserving normal cytoskeletal morphology, stabilizing the cell cycle, and decreasing the apoptosis ratio. The SU-COS intervention also demonstrated a reparative effect on UVB-damaged mouse skin by reducing skin erythema and water loss, relieving crusting, and maintaining the epidermis thickness of the skin and the stability of collagen fibers. The observed changes in both in vitro and in vivo results were accompanied by significant modulation of gene and protein expression associated with the cellular cycle, collagen synthesis, extracellular matrix degradation, antioxidant defense, and inflammation. Overall, SU-COS holds immense promise for applications in repairing photodamage.