Photoperoxidation of lens lipids: prevention by vitamin E

Light of visible frequency was observed to initiate peroxidative degradation of lipids of rat lenses when the latter were maintained in organ culture. The extent of degradation was monitored by measurement of malonaldehyde. This photodegradative process, which is possibly triggered by light catalyzed generation of superoxide and its subsequent transformation to other potent oxidants, was observed to be thwarted substantially if the medium of organ culture was fortified with 10-3 and 10-7 M vitamin E (αtochopherol). These studies suggest that vitamin E may be metabolically beneficial by protecting light exposed tissues, such as those in the eye, against photoperoxidative damage concomitant to light-catalyzed generation of oxygen-free radicals. The findings appear relevant to age-associated pathogenesis of cataracts and their possible attenuation. In addition, they provide a basis of pathogenesis in other ocular tissues such as the macula known to undergo age-dependent degeneration. (author)