Abstract
Abstract: :
Purpose:To investigate metabolic changes in rabbit corneas exposed to either UV–A or UV–B radiation, using High–Resolution Magic Angle Spinning (HR–MAS) 1H NMR spectroscopy. Methods:Both corneas of adult albino rabbits were irradiated with UV–A (366 nm; n = 8) or UV–B (312 nm; n = 8) radiation for 8 minutes, once a day for 5 days. Eight days after the last irradiation, the animals were sacrificed and the exposed corneas were excised. The intact samples both of the exposed and of normal (n= 6) corneas were then analysed using HR–MAS 1H NMR spectroscopy on a Bruker Avance DRX600 spectrometer (14.1 T). The metabolic profile of the samples was compared and analysed by multivariate analysis (PCA and SIMCA). Results:Compared to normal tissues, UV–B irradiation caused a significant concentration reduction of several major metabolites in the exposed corneas: ascorbate (91.6% reduction), taurine (71.2%), hypo–taurine (95.1%), choline (87.1%), myo–inositol (78.8%), acetate (51.3%) and alanine (60.0%) (p < 0.05). After UV–A exposure, the levels of ascorbate (47.4% reduction) and taurine (48.1%) were significantly decreased compared to normal corneas. Conclusions:HR–MAS 1H NMR spectroscopy was found to be an efficient tool for analysis of the metabolic profile in intact corneal tissue. The results revealed substantial metabolic alterations of the rabbit corneas exposed to UV–B radiation and some alteration in the UV–A exposed corneas. These observations might contribute to elucidate processes involved in UV induced damage of the anterior segment of the eye and moreover be of importance in the process of UV–cataract development in the lens.
Keywords: radiation damage: light/UV • cornea: basic science • cataract