Raman spectroscopic evaluation of aging and long-wave UV exposure in the guinea pig lens: a possible model for human aging.
The laser Raman optical dissection technique makes it possible to study individual points of minute volumes (2 X 10(-3) microliter) in the intact living lens in vitro. This technique was used to measure the sulfhydryl and disulfide content of 21 distinct points along the visual axis of the guinea-pig lens after aging and long-wave ultraviolet exposure (9-month duration in vivo). To facilitate comparison between different lenses, data was compiled as the intensity ratio of sulfhydryl (2580 cm-1) to a protein reference signal (2731 cm-1) or disulfide (508 cm-1) to phenylalanine (622 cm-1). These 21 ratios for each experiment were plotted as a function of the distance of the point from the nuclear center of the lens to give a visual axis profile. From these profiles we have found that the loss of sulfhydryl can be accelerated in the guinea-pig lens by in vivo ultraviolet exposure (353 nm peak from an incoherent source) for nine months. There is also a subsequent uniform increase in the disulfide content across the visual axis after UV exposure suggesting a direct sulfhydryl to disulfide conversion in the guinea-pig lens.
Barron
B C
BC
School of Chemistry, Georgia Institute of Technology, Atlanta 30332.
Yu
N T
NT
Kuck
J F
JF
D000375:Aging / Q000502:physiology*; D000818:Animals; D004220:Disulfides / Q000032:analysis; D006168:Guinea Pigs; D007908:Lens, Crystalline / Q000032:analysis / Q000528:radiation effects*; D010649:Phenylalanine / Q000032:analysis; D011487:Protein Conformation; D013059:Spectrum Analysis, Raman; D013438:Sulfhydryl Compounds / Q000032:analysis; D014364:Tryptophan / Q000032:analysis; D014443:Tyrosine / Q000032:analysis; D014466:Ultraviolet Rays
D004220:Disulfides; D013438:Sulfhydryl Compounds; D014443:Tyrosine; D010649:Phenylalanine; D014364:Tryptophan