Department of Pharmacognosy, China Pharmaceutical University, Nanjing, 210038, PR China; Key Laboratory of Standardization of Chinese Medicines of Ministry of Education, Shanghai Key Laboratory of Complex Prescription, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, PR China.
Environ Toxicol Pharmacol. 2009 Nov;28(3):357-62. doi: 10.1016/j.etap.2009.06.002. Epub 2009 Jun 23.
Pyrrolizidine alkaloids (PAs) are well-known natural hepatotoxins distributed widely in thousands of plants in the world. Adonifoline (Adon), senecionine (Sene) and monocrotaline (Mono) are retronecine-type PAs, and the present study is designed to observe the effects of intracellular glutathione on toxicity of these three PAs in human normal liver L-02 cells. The ratio of cellular reduced glutathione (GSH) and oxidized glutathione (GSSG) was assayed after L-02 cells were incubated with these three PAs for various times. Results showed that Adon, Sene and Mono all significantly decreased the ratio of GSH/GSSG in L-02 cells in the time- and concentration-dependent manner. The results of 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) and trypan blue staining assay showed that these three PAs all significantly decreased cell viability in L-02 cells when pretreated with 10μM BSO (L-Buthionine-S-R-Sulfoximine) for 24h to deplete intracellular GSH. Further results showed that anti-oxidant compounds such as NAC (N-Acetyl-Cysteine) and GSH could rescue the cytotoxicity caused by these three PAs with BSO pretreatment. Taken together, those results suggest that intracellular GSH plays important roles in regulating the cytotoxicity induced by PAs.
吡咯里西啶生物碱（PAs）是广泛分布于世界上千种植物中的一种天然肝毒素。当卡宾碱（Adon）、千里光宁碱（Sene）和野百合碱（Mono）这三种 retronecine 型 PAs 作用于人类正常肝 L-02 细胞时，本研究旨在观察细胞内谷胱甘肽（GSH）对其毒性的影响。用这三种 PAs 孵育 L-02 细胞不同时间后，测定细胞内还原型谷胱甘肽（GSH）与氧化型谷胱甘肽（GSSG）的比例。结果表明，Adon、Sene 和 Mono 均能显著降低 L-02 细胞内 GSH/GSSG 的比值，且呈时间和浓度依赖性。3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐（MTT）和台盼蓝染色实验结果表明，当 L-02 细胞用 10μM BSO（L-Buthionine-S-R-Sulfoximine）预处理 24h 以耗尽细胞内 GSH 时，这三种 PAs 均显著降低了细胞活力。进一步的结果表明，抗氧化剂化合物如 NAC（N-乙酰半胱氨酸）和 GSH 可以挽救 BSO 预处理后这三种 PAs 引起的细胞毒性。总之，这些结果表明细胞内 GSH 在调节 PAs 诱导的细胞毒性中起着重要作用。
