Bioactive Chitosan Membranes Loaded with Nile Tilapia Skin Peptides Promote Wound Healing Associated with Temporal Inflammatory Modulation.

Bioactive wound dressings that combine structural support with local biological activity are promising for skin repair. Nile tilapia skin peptides (NTSP) have demonstrated wound-healing potential, while chitosan (CS) offers favorable film-forming, biodegradable, and wound-contact properties. Combining these components may provide a structured platform for topical application of bioactive peptides. This study investigated incorporating NTSP into CS membranes and its effects on physicochemical performance and wound healing. CS membranes containing NTSP at 600 or 1000 μg/mL were characterized and evaluated in a full-thickness wound model in Wistar rats; peptide-free and bovine skin peptide-loaded CS membranes served as comparators. FTIR and XRD supported NTSP incorporation through predominantly noncovalent interactions, without forming a separate crystalline phase. NTSP significantly reduced water vapor permeability from 2.80 ± 0.22 g.mm.m-2.day-1.kPa-1 in control membranes to 1.78 ± 0.16 and 1.63 ± 0.24 g.mm.m-2.day-1.kPa-1 at 600 and 1000 μg/mL, respectively (p < 0.05). The 600 μg/mL membrane showed the highest swelling in simulated exudate fluid (2250.39 ± 64.98% at 24 h; p < 0.0001 vs control), whereas all formulations underwent progressive lysozyme-mediated degradation. Tensile strength decreased with peptide loading, with a significant difference between control and 1000 μg/mL membranes (p = 0.0181). On day 7, wound contraction reached 45.56 ± 8.22% and 55.73 ± 15.39% for the 600 and 1000 μg/mL membranes, compared with 36.60 ± 3.36% for peptide-free CS and 9.97 ± 2.98% for the bovine-peptide comparator. At day 14, the 600 μg/mL formulation remained superior to the 1000 μg/mL and bovine-peptide groups (p = 0.0157 and p = 0.0016). Histological and immunohistochemical findings showed temporal changes in inflammatory-cell recruitment, angiogenesis, fibroblast accumulation, matrix deposition, and TNF-α and IL-6 expression. Overall, the 600 μg/mL NTSP-loaded CS membrane provided the most favorable balance between material performance and biological response, supporting its development as a structured bioactive wound dressing.