Comparison of cytotoxicity of cysteine and homocysteine for renal epithelial cells
Comparison of cytotoxicity of cysteine and homocysteine for renal epithelial cells
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DOI：
10.1159/000084108
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发表时间：
2005-01-01
影响因子：
--
通讯作者：
Izumi, M
中科院分区：
文献类型：
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作者：
Nakanishi, T;Akabane, ER;Izumi, M
背景资料：虽然半胱氨酸（Cys）对肾细胞的细胞毒性作用已经确定，但引起内皮细胞功能障碍的同型半胱氨酸（Hcy）的作用尚未得到很好的测试。比较了同型半胱氨酸和半胱氨酸对肾小管细胞的直接毒性，并探讨了细胞毒性的机制。方法：LLC-PK 1细胞与含有500 μ M Cys或Hcy的测试培养基在存在或不存在100 μ M铜的情况下孵育。乳酸脱氢酶释放和硫代巴比妥酸反应物质分别用于估计细胞溶解和脂质过氧化。分别采用东莨菪内酯法、水杨酸捕获法和谷胱甘肽（GSH）含量法分析过氧化氢和羟自由基的产生以及细胞氧化还原状态。超氧化物歧化酶、过氧化氢酶和维生素E也被用来阐明毒性机制。结果：在铜（+ Cu）存在的情况下，Cys作用16 h后的细胞溶解比Hcy作用更明显。按照细胞毒性，脂质过氧化作用在4小时的孵育，以及过氧化氢和羟基自由基的形成在较短的孵育，Cys +铜显着大于Hcy +铜。Hcy的添加显著降低了GSH含量，而Cys则无此作用。结论：在铜离子存在下，Cys对肾细胞的毒性明显强于Hcy。Hcy的细胞毒性可能依赖于细胞GSH的耗竭，而Cys的细胞毒性主要依赖于活性氧和脂质过氧化的产生。版权所有（C）2005 S. Karger AG，巴塞尔。
Background: Although the cytotoxic effects of cysteine (Cys) on renal cells have been established, the effects of homocysteine (Hcy), which causes endothelial cell dysfunction, have not been well tested. We compared the direct toxicity of Hcy on renal tubular cells to that of Cys and examined the mechanism of cell toxicity. Methods: LLC-PK1 cells were incubated with test media containing 500 mu M Cys or Hcy in the presence or absence of 100 mu M copper. Lactate dehydrogenase release and thiobarbituric acid reactive substance were measured for estimating cytolysis and lipid peroxidation, respectively. The generation of hydrogen peroxide and hydroxyl radical, and the cell redox state were analyzed using the scopoletin method, salicylate-trap method, and glutathione (GSH) content, respectively. Superoxide dismutase, catalase, and vitamin E also were used for clarifying the mechanism of toxicity. Results: In the presence of copper (+ Cu), cytolysis at 16 h was more prominent in cells exposed to Cys than Hcy. In accordance with cytotoxicity, lipid peroxidation at 4 h of incubation, as well as hydrogen peroxide and hydroxyl radical formation in a shorter incubation, were remarkably greater in Cys + Cu than Hcy + Cu. The addition of Hcy, but not Cys, decreased GSH content significantly. Conclusion: In the presence of copper, Cys was extraordinarily more cytotoxic to renal cells than Hcy. Cytotoxicity from Hcy may be dependent upon depletion of cellular GSH, while Cys cytotoxicity is primarily dependent upon the generation of reactive oxygen species and lipid peroxidation. Copyright (C) 2005 S. Karger AG, Basel.