Efficacy of retinol palmitate eye drops for dry eye in rabbits with lacrimal gland resection

Akito Odaka,1 Hiroshi Toshida,2 Toshihiko Ohta,2 Nobuhito Tabuchi,3,4 Daisuke Koike,4 Chikako Suto,3 Akira Murakami31Human and Environmental Safety Evaluation Center, Lion Corporation, Kanagawa, Japan; 2Department of Ophthalmology, Juntendo University Shizuoka Hospital, Shizuoka, Japan; 3Department of Ophthalmology, Juntendo University School of Medicine, Tokyo, Japan; 4Pharmaceutical Research Laboratories No 1, Research and Development Headquarters, Lion Corporation, Kanagawa, JapanPurpose: We examined the efficacy of retinol palmitate (VApal) for dry eyes using dry eye model rabbits whose lacrimal glands were resected.Materials and methods: After alkaline injury on keratoconjunctival epithelium, VApal eye drops were administered 6 times a day for 7 days. The efficacy of VApal was also compared with that of 0.1% hyaluronic acid eye drops.Results: The fluorescein staining and rose bengal scores showed a significant decrease compared with the score in the vehicle group at 7 days (P < 0.05) in the 1000 IU/mL VApal group and at both 3 days (P < 0.05) and 7 days (P < 0.01) in the 1500 IU/mL VApal group. Histological examination revealed recovery of the corneal epithelium, and PAS staining disclosed the recovery of mucin-producing lower palpebral conjunctival goblet cells after 7 days in the 1500 IU/mL VApal group compared with the vehicle group. Results from impression cytology showed a significant increase in density of conjunctival goblet cells compared with that in the vehicle group after 7 days in the 1000 IU/mL VApal group and after 3 and 7 days in the 1500 IU/mL VApal group. There were no significant changes in tear flow in either group. Topical application of VApal at 1500 IU/mL showed greater improvement than 0.1% hyaluronic acid in both fluorescein and rose bengal score and in the density of conjunctival goblet cells.Conclusion: It is suggested that VApal is effective for the improvement of keratoconjunctival epithelial damage associated with tear abnormalities, such as dry eyes.Keywords: cornea, dry eye, hyaluronic acid, vitamin A, wound healing, retinol palmitat