Lockhart B, Jones C, Cuisinier C, Villain N, Peyroulan D, Lestage P
Institut de Recherches Servier, Division of Cerebral Pathology, 78290 Croissy-sur-Seine, France.
Brain Res. 2000 Feb 14;855(2):292-7. doi: 10.1016/s0006-8993(99)02372-0.
In the present report, we have set out to investigate the potential capacity of both the oxidised and reduced forms of RS-alpha-lipoic acid, and its separate R-(+) and S-(-)enantiomers, to prevent cell death induced with L-homocysteic acid (L-HCA) and buthionine sulphoximine (BSO) in rat primary cortical and hippocampal neurons. L-HCA induced a concentration-dependent neurotoxic effect, estimated by cellular 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) reduction, in primary neurons, but was significantly more toxic for hippocampal (EC(50)=197 microM) compared with cortical neurons (EC(50)=1016 microM) whereas D-HCA demonstrated only moderate (<20%) toxicity. On the other hand, cortical and hippocampal cultures were equally susceptible (341 and 326 microM, respectively) to the neurotoxic action of BSO. Antioxidants including butylated hydroxyanisole, propyl gallate and vitamin E protected cells against the neurotoxic effect of L-HCA and BSO. However, N-acetyl-cysteine and tert-butylphenyl nitrone, although capable of abrogating L-HCA-mediated cell death showed no protective effect against BSO-mediated toxicity. RS-alpha-lipoic acid, RS-alpha-dihydrolipoic acid and the enantiomers R-alpha-lipoic acid and S-alpha-lipoic acid protected cells against L-HCA-mediated toxicity with EC(50) values between 3.1-8.3 microM in primary hippocampal neurons and 2.6-16.8 microM for cortical neurons. However, RS-alpha-lipoic acid, RS-alpha-dihydrolipoic acid, and S-alpha-lipoic acid failed to protect cells against the degeneration induced by prolonged exposure to BSO, whereas the natural form, R-alpha-lipoic, was partially active under the same conditions. The present results indicate a unique sensitivity of hippocampal neurons to the effect of L-HCA-mediated toxicity, and suggest that RS-alpha-lipoic acid, and in particular the R-alpha-enantiomeric form is capable of preventing oxidative stress-mediated neuronal cell death in primary cell culture.
在本报告中，我们着手研究氧化型和还原型RS-α-硫辛酸及其单独的R-(+)和S-(-)对映体预防L-高半胱氨酸（L-HCA）和丁硫氨酸亚砜胺（BSO）诱导的大鼠原代皮质和海马神经元细胞死亡的潜在能力。L-HCA在原代神经元中通过细胞3-(4,5-二甲基噻唑-2-基)-2,5-二苯基溴化四氮唑（MTT）还原法诱导浓度依赖性神经毒性作用，但与皮质神经元（半数有效浓度[EC(50)]=1016μM）相比，对海马神经元毒性显著更高（EC(50)=197μM），而D-HCA仅表现出中度（<20%）毒性。另一方面，皮质和海马培养物对BSO的神经毒性作用同样敏感（分别为341和326μM）。包括丁基羟基茴香醚、没食子酸丙酯和维生素E在内的抗氧化剂可保护细胞免受L-HCA和BSO的神经毒性作用。然而，N-乙酰半胱氨酸和叔丁基苯基硝酮虽然能够消除L-HCA介导的细胞死亡，但对BSO介导的毒性无保护作用。RS-α-硫辛酸、RS-α-二氢硫辛酸以及对映体R-α-硫辛酸和S-α-硫辛酸可保护细胞免受L-HCA介导的毒性，在原代海马神经元中EC(50)值在3.1 - 8.3μM之间，对皮质神经元为2.6 - 16.8μM。然而，RS-α-硫辛酸、RS-α-二氢硫辛酸和S-α-硫辛酸未能保护细胞免受长时间暴露于BSO诱导的变性，而天然形式的R-α-硫辛酸在相同条件下具有部分活性。目前的结果表明海马神经元对L-HCA介导的毒性作用具有独特的敏感性，并表明RS-α-硫辛酸，尤其是R-α-对映体形式能够预防原代细胞培养中氧化应激介导的神经元细胞死亡。
