Investigation of the effect of rosmarinic acid on healing in corneal wounds

Objective: Conventional treatment approaches primarily aim to support re-epithelialization and prevent secondary infections; however, their effectiveness is often limited by inadequate control of inflammation and suboptimal retention time on the ocular surface. Therefore, there is increasing interest in developing novel topical agents that not only accelerate epithelial repair but also modulate the inflammatory response and enhance drug bioavailability. In this thesis study, it was aimed to investigate the effects of rosmarinic acid on corneal wound healing. Materials and Methods: In this study, a total of 51 adult female Sprague-Dawley rats were used. Corneal injury was induced in 51 eyes divided into three groups: control, chitosan, and rosmarinic acid+chitosan groups. A 3 mm diameter corneal wound was created in the left eye of each rat. Following corneal injury induction, fluorescein staining was performed at 0, 12, 24, 36, 48, 60, 72, and 84 hours, and photographs were taken under cobalt blue light. Corneal wound images were obtained using a ruler, slit lamp, and camera and transferred to a computer environment. Using the ImageJ software, the lesion margins were marked with the polygon method, measured in µm², and recorded. At the 36th and 84th hours, euthanasia was performed and samples were collected for histopathological examination. Results: In the present study, the rosmarinic acid+chitosan was observed to be more effective in lesions of equal size at the 12th, 24th, 36th, 48th, 60th, 72nd, and 84th hours. Furthermore, histopathological examinations also demonstrated superior outcomes in the rosmarinic acid+chitosan group. Conclusions: The findings of this study clearly demonstrate that local application of rosmarinic acid+chitosan provides a significant therapeutic advantage in experimental corneal epithelial wound healing. Compared with both the control and chitosan-only groups, the combined formulation resulted in faster wound closure, significant reduction in lesion size at all evaluated time points, and improved clinical healing outcomes. These results confirm that rosmarinic acid, when administered through an appropriate carrier system, plays a critical role in accelerating epithelial regeneration.