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

Abstract 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 VEGFA (vascular endothelial growth factor A) and TNFα genes at all time points. 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.