Comparative study on aging, UV treatment, and radiation on cataract formation

Four randomized groups of male mice Fl (C57Black/CBA) were investigated: (a) UV-irraidated (UV-A, 15 min daily over 10 months, 51 ± 7 W/m²); (b) γ-ray irradiated (2 Gy), single; (c) influence of combination of UV- and γ-ray treatment; (d) aging. The lens opacities were measured at the seventh and tenth month. An expert method based on a six-point scale was used for cataract measurement. At the seventh month, the median of lens opacities were Aging group = 0; UV-irradiated group = 2.5; γ-irradiated group = 4.75; γ- and UV-irradiated group = 6.0. The difference between all groups was significant (p < 0.004, Kruskall-Wallis ANOVA test). The Conover post hock test has shown a significant difference for all comparison pairs (p < 0.002) with the exception of the γ- and UV-irradiated group. At the tenth month, the lens opacities strongly increased: Aging group = 2.5; UV-irradiated group = 5.0; γ-irradiated group = 6.5; γ- and UV-irradiated group = 7.5 (median). The difference between groups was significant (p < 0.0001, Kruskall-Willis ANOVA test). The Conover post hock test has shown a significant difference for all comparison pairs (p < 0.003) with the exception of the UV-irradiated group and γ-irradiated group. No formation of specific lens opacities for any group was found. Morphology and protein composition were investigated at the tenth month. The results of a study of morphological changes show destructive and degenerative impairments of the capsule, epithelium cages, and lens fibers. However, no specific changes related to certain particular actions have been found. In addition, there were no specific changes in the protein composition of either water-soluble and water-insoluble fractions estimated by the differential gel electrophoresis technique. The data mean that aging, UV treatment, and γ-radiation causes similar lens changes. It was supposed that UV treatment and/or γ-radiation act as an aging factor on the lens.