Ascorbic acid spares alpha-tocopherol and prevents lipid peroxidation in cultured H4IIE liver cells.
Ascorbic acid, or vitamin C, can recycle alpha-tocopherol in lipid bilayers, but even sparing of alpha-tocopherol has not been a consistent finding in intact cells. Therefore, we tested the ability of ascorbate loading to spare alpha-tocopherol and to prevent lipid peroxidation of cultured H4IIE rat liver cells. Although alpha-tocopherol was undetectable in H4IIE cells, its cell content was increased by overnight incubation with alpha-tocopherol in culture. Cells incubated with ascorbate 2-phosphate accumulated ascorbate to concentrations as high as 0.6 mM after overnight loading, but also released ascorbate into the medium. Ascorbate loading of alpha-tocopherol-treated cells spared alpha-tocopherol in a concentration-dependent manner during overnight incubation. Lipid peroxidative damage, measured as a decrease in fluorescence of cell-bound cis-parinaric acid, was decreased in cells loaded with either alpha-tocopherol or ascorbate 2-phosphate, and showed an additive effect. These results suggest that ascorbate loading of H4IIE cells spares cellular alpha-tocopherol and either directly or through recycling of alpha-tocopherol prevents lipid peroxidative damage due to oxidant stress in culture.
Huang
Junjun
J
Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232-6303, USA.
May
James M
JM
D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology*; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects*; D051381:Rats; D024502:alpha-Tocopherol / Q000378:metabolism* / Q000494:pharmacology
D005231:Fatty Acids, Unsaturated; D024502:alpha-Tocopherol; C013641:parinaric acid; D001205:Ascorbic Acid