A novel ex vivo model of equine corneal wound healing

Corneal disease is a significant cause of decreased vision or blindness in the horse worldwide. Numerous topical and systemic drugs over a prolonged period of time may be used to treat an equine corneal ulcer. Despite the high prevalence of corneal disease and ulceration in the horse, and the complexity of corneal wound healing, research is limited and more heavily devoted to in vivo studies whose limitations include small sample sizes and ethical considerations. Bench top laboratory in vitro studies are limited in number and overlook the complexity of corneal wound healing by assessing each corneal layer separately from its neighbor. The objective of this study was to develop a novel ex vivo model of equine corneal wound healing that maintained structural integrity, and is physiologically relevant, mimicking in vivo events. In this randomized and controlled study, fourteen equine corneas were harvested within two hours of humane euthanasia for reasons unrelated to this study. All donors were screened and corneas were included if they were free of ocular and systemic disease. Corneas were immediately processed and corneoscleral rims excised 2 mm posterior to the limbus. Corneas were randomly assigned to one of the following groups: wounded (n=8) or unwounded (n=6) controls. Each pair of eyes was divided such that corneas from the same horse were assigned to a different group. In the event that only one of the two eyes was included, the eye was assigned to the wounded group. In the ‘wounded’ group, the axial cornea was wounded for 60 seconds