Effect of UVA and UVB Irradiation on the Metabolic Profile of Rabbit Cornea and Lens Analysed by HR-MAS ¹H NMR Spectroscopy

Abstract

Purpose:The aim of the study was to investigate the metabolic profiles of intact rabbit corneas and lenses exposed to UVA and UVB radiation by using high-resolution (HR) magic angle spinning (MAS) ¹H nuclear magnetic resonance (NMR) spectroscopy and pattern recognition methods. Methods:Adult albino rabbits were exposed to UVA (366 nm, 0.589 J/cm²) or UVB (312 nm, 1.667 J/cm²) radiation for 8 min, once a day for 5 days. Three days after the last irradiation day, samples of corneas and lenses were dissected. HR-MAS ¹H NMR spectroscopy combined with pattern recognition methods (principal component analysis and soft independent modelling of class analogy) and one-way ANOVA were applied to obtain metabolic information from intact corneal and lens tissue. Results: UVB irradiation caused statistically significant metabolic changes in the rabbit corneas. A decrease in metabolites as ascorbate (84%), myo-inositol (59%), hypotaurine (91%) and choline (76%) was observed. Exposure to UVA radiation caused no significant metabolic alteration in this tissue. The metabolic profile of the rabbit lenses showed no detectable changes after UVA or UVB exposure. Conclusions:The combination of HR-MAS ¹H NMR spectroscopy and multivariate methods proved effective to analyse intact corneal and lens tissue after exposure to UV radiation of different wavelengths. By avoiding extraction methods and obtaining complete metabolic profiles from one sample, HR-MAS ¹H NMR spectroscopy provided important information about metabolic alteration occurring in rabbit corneal and lens tissue after UV exposure.

Effect of corneal epithelium on ultraviolet-A and riboflavin absorption

“…Ultraviolet rays can induce production of reactive oxygen species and cell death in cultured corneal cells. To protect against these effects, there is a high ascorbate concentration and anti-oxidant enzymes in the corneal epithelium that absorbs portions of the irradiation, thereby protecting deeper eye structures (18,19) . While the integrity of the epithelium can protect the underling structures from UVA penetration, it may act as a barrier, reducing the effects of CXL.…”

Characterization of brain metastases using high‐resolution magic angle spinning MRS

“…High-resolution magic angle spinning (HR-MAS) is an ex vivo MRS technique which has become important for analyzing metabolic information from intact tissue specimens of different origins (13)(14)(15)(16)(17)(18). Comparisons of HR-MAS and conventional MR spectra of perchloric acid extract have produced similar results (18,19).…”

“…MR spectra contain a large number of variables (chemical shifts), and multivariate analysis is very useful for comparing groups of such data. In a variety of medically related applications, multivariate analytical methods such as principal component analysis (PCA) and partial least squares regression analysis (PLS) have been used to investigate spectral correlations with clinical parameters (15,20,26).…”

The effect of single and repeated UVB radiation on rabbit cornea

“…However, since our research group has introduced HR-MAS 1 H NMR spectroscopy into the animal eye research [28], the metabolic profile of the eye segments can be easily analysed [28,29,[33][34][35][36], and the effect of the repeated UV radiation exposure can be evaluated.…”