Biochemical Analysis of Inter-Connection between Types of Nuclear Opacity, Oxidative Stress and Glycation in Cataractous Lens

Lee, Kwang Won; Kim, Jang Hyun; Shin, Du Sik; Kim, Jung A; Chung, Sung Kun; Lee, Jin Hak; Joo, Choun Ki

Abstract

PURPOSE: To elucidate the inter-connection between lens nuclear opacity and its proposed two main factors, which are oxidative stress and glycation reaction initiated with sugars and proteins.
METHODS
We have collected clinical samples after cataract surgery from 57 patients during 3 month period. We also classified these samples into three groups as initial, intermediate and advanced stages, and performed the biochemical assays for measurements of glutathione(GSH) and advanced glycation end products(AGEs).
RESULTS
It showed that the concentrations of GSH in lens soluble proteins were 0.022+/-0.019, 0.017+/-0.011, and 0.011+/-0.010 nmoles/mg lens protein in initial stage, intermediate stage and advanced stage, respectively. Fluorophore formation(Ex370/Em440), which has been reported to represent general AGEs formation, was positively correlated with nuclear opacity showing that 108.8+/-48.3, 174.7+/-116.9, and 188.2+/-130.6 Fluorescence Unit(F.U.) in initial stage, intermediate stage and advanced stage, respectively. Likewise, a marker for AGEs, pentosidine-related fluorophore(Ex335/Em385) was increased with nuclear opacity(67.0+/-30.8, 75.5+/-36.4, and 80.4+/-41.7 F.U. in initial stage, intermediate stage and advanced stage, respectively), although significant differences existed between groups.
CONCLUSION
Our results showed that there are clear inter-connection between lens nuclear opacity, oxidative stress and the formation of general AGEs compared with pentosidine, and suggested that therapy using antioxidants, chelating agents, or glycation inhibitors could be beneficial in delaying nuclear cataractogenesis.