Chitosan and chitosan–silver nanoparticles as adjuncts to platelet-rich plasma in canine full-thickness cutaneous wound healing

Enhancing full-thickness cutaneous wound repair in dogs remains challenging, particularly when infection risk and delayed regeneration are expected. Platelet-rich plasma (PRP) delivers a concentrated pool of growth factors, while chitosan-based nanoparticles-especially silver-functionalized systems-may provide antimicrobial protection and support tissue remodeling. This study evaluated PRP alone or combined with chitosan nanoparticles (PRP/CS NPs) or chitosan-capped silver nanoparticles (PRP/CS/Ag NPs) in experimentally induced full-thickness skin wounds in dogs. Twenty-four healthy male mongrel dogs were randomized into four groups (n = 6): saline control, PRP, PRP/CS NPs, and PRP/CS/Ag NPs. Standardized 2 × 2 cm full-thickness wounds were created surgically and followed for 21 days using clinical wound assessment, wound area and contraction measurements, histopathology, collagen deposition analysis, and immunohistochemical staining for EGF and α-SMA. All treatments significantly reduced wound size and increased contraction versus controls over time (p < 0.001). PRP/CS/Ag NPs achieved the greatest wound size reduction, particularly on days 7, 14, and 21, with a significant difference from controls at day 14 (p < 0.001). PRP promoted higher early collagen deposition (day 7), whereas PRP/CS/Ag NPs induced sustained and significantly greater collagen deposition at days 14 and 21. Immunohistochemistry showed consistently higher EGF expression in the PRP/CS/Ag NPs group across time points, while PRP/CS NPs increased α-SMA expression, consistent with enhanced myofibroblast activity. PRP accelerates early wound repair, while chitosan-based nanoparticles modulate later healing events.PRP combined with PRP/CS/Ag NPs produced the most consistent improvement in wound closure, collagen remodeling, and epithelial regeneration, supporting silver-functionalized chitosan nanoparticles as a promising adjunct to PRP for managing full-thickness cutaneous wounds in dogs.