The healing effect of all-trans retinoic acid on epithelial corneal abrasions in rabbits

PURPOSE: The aim of the study was to investigate the possible healing effect of the vitamin A analogue all-trans retinoic acid 0.05% (RA) in vaseline on epithelial corneal abrasions in 13 ocularly healthy Copenhagen white rabbits.

METHODS: A corneal abrasion with a diameter of 6 mm was created centrally in both eyes with a trephine and subsequent rubbing off of the corneal epithelium with an n-heptanol soaked swab The corneal abrasions were treated twice daily with topical applications (50 microl); RA was placed in the right inferior fornix and its vaseline vehicle in the left inferior fornix. Photographic documentation of fluorescein stained, non-healed areas, was performed at time points 0, 12, 24, 36, 48 and 72 h. The rabbits were sacrificed by an overdose of pentobarbital and enucleated. Planimetry was performed from corneal photographs.

RESULTS: Healed epithelial mean area at time point 36 h was significantly higher after RA compared to vehicle (p=0.036, paired t-test). Median time to 75% and 85% healing was significantly shorter for RA compared to vehicle (p= 0.03 and 0.02, log rank-test). No morphological difference, evaluated by light microscopy (hematoxylin-eosin) or scanning electron microscopy, was noted between the two treatments.

CONCLUSION: It is concluded that RA 0.05% applied twice daily increases the healing rate compared to vaseline vehicle.