High-Resolution MAS ¹H NMR Spectroscopic Analysis of Rabbit Cornea After Treatment with Dexamethasone and Exposure to UV-B Radiation

Abstract

Metabolic changes in rabbit cornea after combined long-term steroid treatment and UV-B exposure were investigated. Corneas were exposed to UV-B radiation (2.05 J/cm²) after 36 days topical pretreatment with either 0.1% dexamethasone or saline. Twenty-four hours after UV-B exposure, corneas were excised and aqueous humour aspirated. Intact corneal tissues were analyzed by magic angle spinning proton NMR spectroscopy and pattern recognition methods. UV-B decreased corneal ascorbate (63% reduction), taurine (62%), and choline (63%), whereas glucose was elevated. Dexamethasone pretreatment further depleted corneal taurine and ascorbate, decreased aqueous ascorbate (85%), and accumulated glucose in cornea and aqueous humour. The results reflect antioxidative mechanisms and osmoregulation.

KEYWORDS:

• aqueous humour
• cornea
• dexamethasone
• magic angle spinning
• UV-B