Age-related changes of serum lipoprotein oxidation in rats.
Oxidation of low-density lipoprotein (LDL) may be a prelude to atherogenesis and directly age related. To assess whether there may be relationship between age and plasma lipoprotein (LP) oxidation, we studied copper-mediated LP oxidation isolated from the blood of 2 months, 7 months, and 15 months old rats. We determined whether the susceptibility of LP to oxidation might be related to vitamin C levels in serum, vitamin E levels in LP, or the total antioxidant capacity (TAC) of serum or LP. Serum vitamin C content was inversely related to age, malondialdehyde (MDA) propagation rate, and maximum change of MDA concentrations. However, there were no significant relationships between age and serum TAC, LP TAC, serum vitamin E, or the ratio of LP vitamin E to serum vitamin C content. The lag phase of MDA formation was significantly decreased with age and the ratio of LP vitamin E content to serum vitamin C content, increased with age. Maximum change of MDA concentration was positively correlated with the ratio of LP vitamin E contents to serum vitamin C concentration. Thus, as the rat ages, vitamin C status decreases with an increased LP susceptibility to oxidation. It is tempting to speculate that enhanced LP oxidation in older rats may reflect a reduced amount of recycling of LDL vitamin E by serum vitamin C.
Nakamura
Yukiko Kawashima
YK
Department of Nutrition, University of Nevada, Mail Stop 142, Reno, NV 89557, USA.
Omaye
Stanley Teruo
ST
D000375:Aging / Q000378:metabolism*; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001205:Ascorbic Acid / Q000097:blood; D001835:Body Weight / Q000502:physiology; D007202:Indicators and Reagents; D008074:Lipoproteins / Q000097:blood*; D008297:Male; D010084:Oxidation-Reduction; D051381:Rats; D017207:Rats, Sprague-Dawley; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D014810:Vitamin E / Q000378:metabolism
D000975:Antioxidants; D007202:Indicators and Reagents; D008074:Lipoproteins; D017392:Thiobarbituric Acid Reactive Substances; D014810:Vitamin E; D001205:Ascorbic Acid