Aging alters antioxidant enzyme activities in the aorta from fischer-344 rats
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Oxidative stress imposed by reactive oxygen species is believed to contribute to aging. Accumulating evidence also suggests that oxidative stress contributes to deposition of atherosclerotic plaques in the vasculature. The antioxidant enzymes glutathione peroxidase (GPX), superoxide dismutuse (SOD), and catalase (CAT) play a crucial cellular role in defending against the ravages of oxidative stress. Our purpose was to characterize age-related changes in SOD, GPX, and CAT with aging in the rat aorta. Aortas were extracted from 7 young (Y: 4 mo. old), 7 mature (M: 18 mo.), and 7 old (O: 24 mo.) animals, quickly frozen in liquid nitrogen, and stored at -80 until biochemical analyses. ANOVAs with Fisher-LSD post-hoc were performed to determine if age differences existed for GPX, SOD, and CAT. GPX activities for the aorta showed significant differences among all three groups with the mature animals displaying the highest activities (SEM) expressed m umol/min/gm w.w (Y: 4.691 0.471; M: 8.946 0.733; O: 6.841 0.220). No significant age differences in SOD were found. CAT activities showed a different pattern with old rats having significantly lower activity expressed in U/gm w.w. than in the young and mature age groups (Y: 7.446 1.224; M: 7.881 0.912; O: 4.443 0.717) GPX/CAT ratios increased progressively and significantly with increasing age (Y: 0.639 0.950; M: 1.171 0.760; O: 2.042 0.559). These data indicate that aging alters the antioxidant enzyme profile of the rat aorta.