Glycation of lens proteins in relation to aldose reductase activity and galactose-induced cataracts

J. P. Glover, J. L. Jacot, C. M. Rao, C. Qin, J. S. Zigler, W. G. Robison

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Abstract

Purpose. To determine the contribution of glycation to the formation of cataracts in the galactose-fed rat model of diabetic ocular complications. Methods. Rats were fed ad libitum diets consisting of Purina (#5001) plus 50% starch (CON) or 62% D-galactcse without (GAL) or with (ARI) the aldose reductase inhibitor Alcon 1576 (0.02% w/w). Cataract development was assessed by slit-lamp biomicroscopy. Rats were euthanized at various intervals and the lenses removed, decapsulated and homogenized in pairs. The water soluble (WS) and urea soluble (US) components were separated. Percentages of glycated proteins were determined by a modified affinity chromatography procedure (Glyc-Affin GHb, Isolab Inc.) with spectrophotometric quantitation of proteins. Synchronous scan fluorescence spectroscopy was performed on all fractions. Results. Cataracts developed within three weeks in the GAL rats, but did not develop in the ARI and CON rats. In both the WS and the US fractions, the percentages of glycated lens proteins were significantly elevated in GAL and ARI rats compared to CON. In the GAL rats, the WS nonglycated fraction exhibited a yellowish coloration and autofluorescence which increased with galactosemic duration and were not present or were substantially diminished in the other fractions. Conclusions. Aldose reductase activity rather than glycation of lens proteins appears to play the major role in the initial rapid cataract development in galactose-fed rats. Glyoxidation end products, of the WS "nonglycated" fraction, instead of initial glycation products may play a role in the slower, cumulative yellowing and autofluorescence.

Original languageEnglish (US)
Pages (from-to)S601
JournalInvestigative Ophthalmology and Visual Science
Volume37
Issue number3
StatePublished - Feb 15 1996

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

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