Aging and cataractous process of the lens detected by laser Raman spectroscopy

Raman spectra from the lenses of rat and mouse were measured in situ at various conditions of lens aging and opacification. Laser Raman spectroscopy is a powerful nondestructive structural probe to provide us useful informations such as hydration or dehydration state, thiols and its oxidation or micro-environmental state of tryptophan or tyrosine residuse of the lens proteins. In this paper we summurized our Raman studies on various normal, aged and cataractous lenses. Lens dehydration was a common phenomena during normal aging. Regional distribution of lens water showed lens fiber aging from nucleus to cortex. On the other hand lens hydration was a common in the lens with opacification. Using regional water content as a diagnostic marker, the effect of aldose reductase inhibitor was monitored objectively. Lens slfhydryl (SH) groups were reduced with age and with opacification in general, and concomitant increase in disulfide (S-S) bonds was detected. In ICR/f rat lens the decrease in SH groups and simultaneous increase in S-S bonds were found even before lens opacity was manifest.