Abstract
Corneal injuries are a major clinical entity in veterinary ophthalmology, resulting in chronic inflammation, corneal scarring, ulceration, and blindness. Corneal injuries caused by alkali are particularly damaging because of the high diffusibility of alkaline agents into the corneal stroma, resulting in a large area of cell destruction, reducing epithelial regeneration, and prolonging inflammatory responses. This study aimed to evaluate the effects of nano-zinc oxide and platelet-rich plasma on corneal injury healing in rabbits. Twenty adult rabbits (mean ± SD: 1.5 ± 0.5 kg) were randomly assigned to four experimental groups: negative control (n = 2, normal cornea); positive control (n = 6, untreated corneal injury); PRP-treated group (n = 6, double-dose PRP administration on days 1 and 2 post-injury); and nano-ZnO-treated group (n = 6, topically administered Nano zinc oxide 20 µg/day for 7 days). A 0.5-cm alkali (NaOH) burn was performed aseptically to induce corneal injury under general anesthesia. Corneal wound healing was evaluated both clinically and by histopathologic examination at 0, 7, 14, and 28 days post-injury using fluorescein dye testing. Clinically, all groups developed severe corneal opacity and ulceration immediately after injury. Inflammation progressively decreased and was resolved by the end of the experiment, resulting in the recovery of normal corneal transparency in the treated groups, whereas partial inflammation persisted in the controls. Corneal wound healing appeared improved on day 28 compared with day 0 after injury. Qualitatively, fluorescein staining revealed yellow-green portions representing corneal ulceration, which gradually faded in the VAN and CLL groups, indicating complete recovery. Histopathological evidence showed better epithelial healing and normal corneal histology in the Nano-ZnO group compared with the PRP group and both groups compared with the control animals. In conclusion, both zinc oxide nanoparticles and platelet-rich plasma promoted corneal healing in a rabbit’s model, with Nano-ZnO demonstrating the most potent effect. ZnO-NPs and PRP can help repair the cornea by stimulating macrophages and keratocytes. The high antioxidant capacity of ZnO-NPs and platelet-rich plasma growth factors can contribute to faster healing. Therefore, our results suggest the potential pharmaceutical use of ZnO-NPs and PRP for corneal injury healing in rabbits.

Key words: Corneal; Histopathology; Nano-Zinc Oxide; Platelet Rich Plasma; Rabbits.