A possible mechanism of X-ray-induced injury in rat lens

Purpose: X-ray and other radiation can cause cataract, but the pathogenic m echanism is largely unknown. The aim of this study was to investigate the a ccumulation of iron in the x-ray-exposed rat lens and its relationship to l ens injury. Methods: Fifty male Wistar rats were divided randomly into five groups of 1 0. Groups 2 and 4 rats were sham-exposed, groups 3 and 5 were x-ray-treated , and group 1 served as control. X-ray radiation and sham exposure were per formed in a similar manner. After 10 and 30 days of exposure, a lens from e ach rat in groups 2 and 3, and 3 and 5, respectively, were analyzed by flam e atomic absorption technique for the assessment of metal content. Results: Significantly decreased zinc and increased iron and calcium concen trations were detected in the lens samples of groups 3 and 5 compared with groups 2 and 4 and controls. Similar results were obtained comparing groups 5 and 3. Conclusions: We propose that x-ray exposure may cause toxic cell injury of the rat lens via Fenton metals catalyzed damage. initial lens membrane dama ge in the radiolytic phase may permit the access of iron resulting in lens damage. (C) 2000 Japanese Ophthalmological Society.