Li Xia, Huang Junjun, May James M
Department of Medicine, Vanderbilt University School of Medicine, 715 Preston Research Building II, 2220 Pierce Ave., Nashville, TN 37232-6303, USA.
Biochem Biophys Res Commun. 2003 Jun 6;305(3):656-61. doi: 10.1016/s0006-291x(03)00836-2.
Ascorbic acid is considered an antioxidant in the central nervous system, but direct evidence that ascorbate protects neuronal cells from oxidant stress is lacking. Differentiated SH-SY5Y cells in culture took up ascorbic acid on the sodium-dependent vitamin C transporter Type 2 and retained it much more effectively than dehydroascorbic acid. Intracellular ascorbate spared alpha-tocopherol, both in cells loaded with alpha-tocopherol in culture and in cells under oxidant stress due to extracellular ferricyanide. Sparing of alpha-tocopherol in response to ferricyanide was associated with protection against lipid peroxidation in cell membranes. These results show that neuronal cells concentrate ascorbate, and that intracellular ascorbate, either directly or through sparing of alpha-tocopherol, protects them against oxidant stress.
抗坏血酸在中枢神经系统中被视为一种抗氧化剂，但缺乏抗坏血酸盐保护神经元细胞免受氧化应激的直接证据。培养中的分化型SH-SY5Y细胞通过2型钠依赖性维生素C转运体摄取抗坏血酸，并且比脱氢抗坏血酸更有效地保留它。细胞内抗坏血酸可节省α-生育酚，无论是在培养中加载α-生育酚的细胞中，还是在由于细胞外铁氰化物而处于氧化应激状态的细胞中。响应铁氰化物时α-生育酚的节省与对细胞膜脂质过氧化的保护有关。这些结果表明，神经元细胞会浓缩抗坏血酸，并且细胞内抗坏血酸，无论是直接地还是通过节省α-生育酚，都能保护它们免受氧化应激。
