Wound Care with Grape Skin Extract and Sustainable Materials: Evidence from an In Vivo Rat Model

Background: This study investigates a novel alginate–gelatin hydrogel incorporating polyphenol-rich grape skin extract as a multifunctional therapeutic system for diabetic wound healing. The extract was obtained by ultrasound-assisted extraction and formulated into a biopolymer hydrogel designed to combine optimal moisture retention with the controlled release of bioactive compounds. Methods: A streptozotocin-induced diabetic rat model was used to evaluate wound contraction, collagen deposition, oxidative stress parameters, and systemic inflammatory markers over a 15-day period. Animals were assigned to four groups: untreated control, silver sulfadiazine (SSD), empty hydrogel (EH), and extract-loaded hydrogel (LH). Results: The LH formulation demonstrated superior wound closure, reaching 97.1% by day 15, significantly outperforming SSD and other groups. Hydroxyproline levels were markedly elevated in LH-treated tissues, indicating enhanced collagen synthesis and extracellular matrix formation. Redox analyses revealed substantial reductions in TBARS and significant increases in SOD, CAT, and GSH, confirming the strong antioxidative activity of the incorporated extract. Moreover, LH treatment produced pronounced decreases in IL-6 and TNF-α, restoring inflammatory balance and facilitating timely progression from the inflammatory to proliferative phase. Conclusions: These effects are attributed to the synergistic actions of grape skin polyphenols which exerted broad biochemical and structural benefits essential for diabetic wound repair. Overall, this sustainable, bioactive hydrogel represents a promising alternative for advanced wound care.