Antibacterial and Regenerative Potential of Zinc Oxide Nanoparticles and Carboxymethyl Cellulose for Infected Wound Healing in Rats

Infection remains a critical challenge in wound healing, often delaying recovery and complicating the case. The widespread misuse of antibiotics has further exacerbated this issue by driving antibiotic resistance, creating an urgent need for alternative therapeutic strategies. This study investigates the potential effects of Zinc Oxide Nanoparticles (ZnONPs) combined with Carboxymethyl Cellulose (CMC) as a solution to overcome these barriers. By employing a comprehensive approach, the effect of these materials was evaluated through histopathological, immunohistochemical, and bacteriological analyses, alongside macroscopic observations, which included body weight, wound size, and contraction assessment. Fifty-four male adult Albino Wistar rats were used in this study. A full-thickness circular Staphylococcus aureus-infected skin wound of a 23 mm diameter was induced in all rats. After 3 days, these rats were divided into 3 groups according to the treatment protocol: the infected group (treatment with normal saline 0.9%), the CMC group (treatment with CMC alone), and the CMC/ZnONPs group (treatment with CMC/ZnONPs gel). Rats were then euthanized, and samples were collected for histopathology and immunohistochemistry on days 7, 14, and 21 postoperatively. Swabs were taken from the wounds for bacterial examination on the 2nd, 7th, 14th, and 21st postoperatively. Although the CMC alone enhanced the wound healing, the combination of the CMC and the ZnONPs demonstrates a significantly superior effect by enhancing angiogenesis, reducing inflammation, and accelerating re-epithelialization. Additionally, for CMC to achieve an effective antibacterial effect, it must be applied four times daily, whereas the CMC/ZnONPs gel requires only twice-daily application. Therefore, the incorporation of ZnONPs appears essential for CMC to exert effective antibacterial activity.