Vet Ophthalmol 2003 Jun;6(2):131-4
Large Animal Clinical Sciences, University of Florida, College of Veterinary Medicine, PO Box 100136, Gainesville 32610-0136, USA.
Objective: To determine if opioid growth factor (OGF, [Met5]enkephalin) and its specific receptor (OGFr) are present in normal cat, dog and horse cornea.
Animals Studied: Normal dog, cat and horse.
Procedure: Corneas were obtained from animals euthanized for reasons unrelated to this project. One cornea from each of three normal cats, dogs and horses was evaluated. The right or left cornea from each animal was chosen randomly. Corneas were harvested and placed in corneal storage media for transport to The M.S. Hershey Medical Center of The Pennsylvania State University where immunocytochemistry techniques were used to demonstrate the presence and location of OGF and OGFr. Tissues were rinsed in Sorenson's phosphate buffer, immersed in 20% sucrose in buffer and then snap frozen in isopentane. Corneas were then embedded in OCT medium and 15 micro m cryostat sections were created. Presence of OGF was determined by using a polyclonal antibody to [Met5]enkephalin and assessing immunoreactivity. OGFr presence was determined by using a previously characterized rabbit polyclonal antibody to the receptor.
Results: OGF and OGFr were identified in large quantities in the corneal epithelium of all three species.
Conclusion: Opioid growth factor and its specific receptor are present in the corneal epithelium of normal cats, dogs and horses. OGF is present in the cornea of many species and its presence is theorized to inhibit healing of injured tissue.