Total sulfhydryl by Raman spectroscopy in the intact lens of several species: Variations in the nucleus and along the optical axis during aging

The sulfhydryl concentration in the central nucleus of rat and mouse lenses falls precipitously with age. However in the lenses of man and water buffalo, the sulfhydryl decreases at a much slower rate with age. This difference between the two groups appears to be correlated with the derivation of albuminoid: in the rodents it is chiefly γ-crystallin which gives rise to albuminoid while in human and bovine lenses albuminoid is related to α-crystallin. The sulfhydryl concentration profiles along the visual axis of human, rabbit and chicken lenses of several ages show that these species have profiles unlike those of rat and mouse lenses; the rabbit lens is more like the human lens while the chicken lens is in a class by itself due to the predominance of δ-crystallin in the nucleus and the consequent extremely low concentration of sulfhydryl. The implications of these findings are discussed in relation to changes in the aging lens.