Alteration of lens sulfhydryl groups induced by oxidative stress: Raman spectroscopic study of hydrogen peroxide-treated rat lens.

It has been reported that hydrogen peroxide is present in the aqueous humor and its level is increased in cataract patients. To determine the effect of hydrogen peroxide on the lens, hydrogen peroxide-treated lenses were monitored by Raman spectroscopic methods before and after treatment. The lenses were also examined histologically. Excised rat lenses were incubated in the medium containing 100 mM of hydrogen peroxide for one hour. Slight lens opacification was observed 3 hours after completion of treatment and there was marked opacification by 5 hours. Analysis of the Raman spectra from the lens cortex indicated that sulfhydryl groups were decreased and disulfide bonds were increased, which suggested that exposure to hydrogen peroxide resulted in 2SH --> SS conversion in the lenses. A decrease in sulfhydryl groups was observed at one hour after completion of treatment and its level was decreased to 60% of the control level by 4 hours after treatment. Since the decrease in sulfhydryl groups was observed prior to lens opacification, the results indicated that 2SH --> SS conversion may be related to the formation of lens opacification.