Gabryel Bozena, Toborek Tomasz, Małecki Andrzej
Department of Pharmacology, Silesian Medical University, 18 Medyków St., PL 40752 Katowice, Poland.
Neurotoxicology. 2005 Jun;26(3):373-84. doi: 10.1016/j.neuro.2005.03.004.
The aim of the present study was to test the hypothesis that exposure of astrocytes depleted of glutathione (GSH) to simulated ischemia conditions in vitro and treated with immunosuppressant immunophilin ligands (cyclosporin A (CsA) and FK506) can increase intracellular GSH levels and that such mechanism may be responsible, at least in part, for their protective effects. In addition, we also compared the antioxidant properties of these immunosuppressants with N-acetylcysteine (NAC), a precursor of GSH synthesis. GSH depletion was induced by 24 h pretreatment with L-buthionine sulfoximine (BSO). Cultures of rat astrocytes were exposed to CsA (1-50 microM) and FK506 (1-1000 nM) and NAC (100 or 200 microM). We examined the effects of these compounds on apoptosis, cell viability, reactive oxygen species production and GSH content. Our study demonstrated that toxicity of simulated ischemia conditions were enhanced when intracellular GSH was depleted, and immunosuppressants (especially 100 nM FK506 and 10 microM CsA) effectively prevented ischemia toxicity in GSH depleted astrocytes. In addition, we have shown that interfering with the generation of GSH and attenuation, the rise of oxidative stress level by NAC may be a powerful tool for prevention of ischemia-induced glial cell damage.
体外将缺乏谷胱甘肽（GSH）的星形胶质细胞暴露于模拟缺血条件下并用免疫抑制剂亲免素配体（环孢素A（CsA）和FK506）处理可提高细胞内GSH水平，且这种机制可能至少部分地是其保护作用的原因。此外，我们还将这些免疫抑制剂的抗氧化特性与GSH合成前体N-乙酰半胱氨酸（NAC）进行了比较。通过用L-丁硫氨酸亚砜胺（BSO）预处理24小时诱导GSH耗竭。将大鼠星形胶质细胞培养物暴露于CsA（1-50微摩尔）、FK506（1-1000纳摩尔）和NAC（100或200微摩尔）。我们研究了这些化合物对细胞凋亡、细胞活力、活性氧产生和GSH含量的影响。我们的研究表明，当细胞内GSH耗竭时，模拟缺血条件的毒性会增强，而免疫抑制剂（尤其是100纳摩尔FK506和10微摩尔CsA）可有效预防GSH耗竭的星形胶质细胞中的缺血毒性。此外，我们还表明，干扰GSH的生成并通过NAC减轻氧化应激水平的升高可能是预防缺血诱导的神经胶质细胞损伤的有力工具。
