How exposure to the solar radiation increases the risk of cataract development Human recombinant αA-crystallin as the target protein

The cumulative exposure of eye lenses to ultraviolet and visible light (UV) has been indicated as the important causative player in development of the senile cataract disease. The eye lenses contain different types of UV filters which their levels ultimately decrease with human age. Moreover, upon direct or indirect exposure to the solar radiation, various photosensitizers including riboflavin (RF) actively participate in the photo-damages and opacification of human eye lenses. All of these events increase the rate of senile cataract development particularly in the outworkers. In the current study, the photo-oxidation of human recombinant αA-crystallin in the presence of RF and upon exposure to direct sunlight was analyzed using different spectroscopic assessments and SDS-PAGE mobility shift assay. The RF-mediated photo-oxidation of αA-crystallin led to the reduction in both Trp and Tyr intensities and formation of new chromophores which have been detected by UV-Visible and fluorescence spectroscopic assessments. It should be noted that eye lenses contain many antioxidant compounds protecting them against the destructive photo-damaging molecular events. Therefore, weakness of the powerful antioxidant defense mechanism of eye lenses in diabetic patients may increase the risk of solar radiation-associated cataract development. Our study, suggest that natural lens antioxidant molecules such as glutathione, cysteine and ascorbic acid were capable to significantly prevent the RF-mediated photo-oxidative damages of human αA-crystallin.

کلیدواژه ها:

Cataract ، Photooxidation ، Human αA-crystallin ، Antioxidants