Changes in aqueous humour following single or repeated UVB irradiation of rabbit cornea.

BACKGROUND

Aqueous humour is the main nutritive source for corneal and lenticular tissues, and knowledge of a possible cumulative effect of ultraviolet radiation (UVR) on its metabolic profile might be of great help in the assessment of cataract risks. By using high-resolution (1)H nuclear magnetic resonance (NMR) spectroscopy, it was possible to evaluate the effect of a single and repeated UVB radiation of the rabbit eye with the same overall dose on the aqueous humour.

METHODS

Samples of aqueous humour from twenty-four albino white rabbit eyes were examined for the effects of UVB exposure (312 nm). In the first group (UVB1), four animals were irradiated with a single dose 3.12 J/cm(2) (21 minutes) of UVB radiation. The animals in the second group (UVB2, n = 4) were irradiated three times for 7 minutes every 2nd day (dose of 1.04 J/cm(2); days 1, 3, 5) to give the same overall dose (3.12 J/cm(2)). The third group (n = 4) served as an untreated control group. (1)H NMR spectra of aqueous humour from all eyes were obtained. Special grouping patterns among the tissue samples and relative percentage changes in particular metabolite concentrations were evaluated using appropriate statistical methods (multivariate analysis, Independent sample t-test).

RESULTS

Significant alterations in the metabolic profile of aqueous humour from UVR-B exposed rabbit eyes and an apparent cumulative effect of repeated UVB irradiation were observed.

CONCLUSIONS

Application of a Carr-Purcell-Meiboom-Gill spin echo pulse sequence was found to have a great advantage for correct analysis of the results obtained with NMR spectroscopy of aqueous humour from eyes where increase of protein level due to an inflammatory process could not be excluded.