Effects of topical neutral protamine Hagedorn insulin on corneal wound healing: an experimental study in rabbits

Corneal injuries are common in human and veterinary ophthalmology. There are many studies which have investigated the treatment of corneal epithelial defects. This study aimed to investigate the effects of Neutral Protamine Hagedorn (NPH) insulin as an ointment for wound healing in experimental corneal defects. First, a superficial keratectomy was performed on 12 rabbits using a corneal trephine. The animals were divided into two groups, Group I (treated, n = 6) and Group II (vehicle control, n = 6). Insulin ointment was applied topically once daily in the treated group, and saline ointment was applied in the same manner in the vehicle control group. Corneal defects were observed and photographed, and changes in wound surface were recorded on days 7, 14, 21, 30, and 60. In both groups, a significant reduction in the wound surface area was noticeable on the 30th day after defect creation. Between the 30th and 60th days, while the changes in the wound surface area in Group II remained limited, the decrease continued rapidly in Group I. At the end of the study, the corneal opacity score observed was lower in Group I than in Group II. In conclusion, we determined that topical NPH insulin may accelerate corneal wound healing after superficial lamellar keratectomy. A new alternative treatment may be developed for treating corneal wounds through continuing studies on this subject.