Innovative strategies on accelerating skin wound healing in dogs using chitosan-coated zinc oxide nanoparticles delivered by two different routes.

Introduction: Zinc-oxide nanoparticles (ZnO NPs) have shown promise for their antibacterial, anti-inflammatory and regenerative capabilities. Chitosan-coated metal-oxide NPs have higher solubility and bioactivity than uncoated ones, making them an effective biomaterial for medical uses. This study aimed to exploit the complimentary features of chitosan-coated ZnO NPs (CS/ZnO NPs) to overcome existing limits in wound care treatments. It delivered the nanoparticles by two key routes: subcutaneous (s/c) injection and topical (T) application. Material and Methods: Fifteen dogs were divided into three groups (n = 5) as follows: a control group, a group treated with s/c injection of CS/ZnO NPs (25 ppm) once a week for two weeks and a group treated by daily T application of CS/ZnO NPs (25 ppm) for two weeks. Wounds were monitored grossly and microscopically at 0, 3, 7, 14 and 21 d post treatment. Blood was drawn before the first and after the last treatment for liver and kidney function biomarker and blood morphology evaluation. Results: Administration of CS/ZnO NPs either s/c or T accelerated wound closure without affecting liver or kidney function, but the s/c route caused a significant deterioration in HGB, HCT, RBC, WBC and PLT counts compared with the T route. Microscopic examination revealed improved epithelialisation, decreased inflammatory cell infiltration, greater collagen deposition and superior tissue organisation in wounds treated with CS/ZnO NPs over time, confirmed by increasing vascular endothelial growth factor and α-smooth muscle actin immunoexpression. The nanoparticles also boosted the transcript levels of the Conclusion: This study demonstrates the benefits of nanotechnology in wound care and emphasises the need for additional research to enhance nanoparticle formulations for therapeutic applications.