设为首页加入收藏
文章正文
大量服用硒旺纳米硒作为防癌剂可能更有效
硒旺纳米硒    2017-08-23 15:12:29    文字:【】【】【

Peng D, Zhang J, Liu Q, Taylor EW. Size effect of elemental selenium nanoparticles (Nano-Se) at supranutritional levels on selenium accumulation and glutathione S-transferase activity. Inorg. Biochem. 2007, 101(10):1457-1463. 影响因子3.663 本文来自nano-se.com

论文名称:超营养水平元素硒纳米粒子(纳米硒)的硒积累和诱导脱毒酶谷胱甘肽硫转移酶的尺寸效应

作者:彭敦耕、张劲松等 发表于《无机生物化学》2007bbs.nano-se.com

[Abstract]

It has been shown that 36 nm Nano-Se has lower toxicity than selenite or selenomethionine, but these forms of selenium (Se) all possess similar ability to increase selenoenzyme levels. The size of nanoparticles plays an important role in their biological activity: as expected, 5-200 nm Nano- Se can directly scavenge free radicals in vitro in a size-dependent fashion. However, in Se-deficient cells and Se-deficient mice, the size effect of Nano-Se on increasing selenoenzymes and liver Se disappears unexpectedly. We hypothesize that under conditions of Se deficiency, the avidity of Se uptake mechanisms may be increased to maintain the biosynthesis of selenoenzymes, which are fundamental for redox homeostasis. This increased avidity may override the potential advantage of small size Nano-Se seen under Se-replete conditions, thereby eliminating the size effect. Once selenoenzymes have been saturated, Se uptake mechanisms may downregulate; accordingly, the size effect of Nano-Se can then reappear. To test this hypothesis, Se- deficient mice were administered either 36 or 90 nm Nano-Se at supranutritional doses, in both a short-term model and a single-dose model. Under these conditions, Nano-Se showed a size effect on Se accumulation and glutathione S-transferase (GST) activity. A size effect of Nano-Se was found in 15 out of 18 total comparisons between sizes at the same dose and time in the two models. Furthermore, the magnitude of the size effect was more prominent on Se accumulation than on GST activity. GST is strictly regulated by transcriptional and translational mechanisms, so its increase in activity normally does not exceed 3-fold. In contrast, the homeostasis of Se accumulation is not as tightly controlled. In the present experiments, GST activity had reached or was approaching saturation, but liver Se was far below saturation. Therefore, our results strongly suggest that the saturation profile of the tested biomarker has an impact on the size effect of NanoSe. Since both GST and small molecular weight selenocompounds accumulated in vivo are important intermediates for chemoprevention by Se, our results also suggest that Nano-Se should be most effective as a chemopreventive agent at smaller particle size. (C) 2007 Published by Elsevier Inc.

[文摘]

已报道36 nm纳米硒的毒性低于亚硒酸钠和硒氨酸,但是这些硒形式都具有相近的增加含硒酶活力的作用。纳米颗粒的尺寸对它的生物学活性有重要影响。如预期的一 样,5~200 nm纳米硒体外直接清除自由基依赖于尺寸。然而,在缺硒细胞和小鼠,意想不到的是纳米硒在营养水平增加含硒酶和肝硒不存在尺寸效应。我们假设,在硒缺 乏情形下,硒摄入的动力可能会增加,以便于维持含硒酶的生物合成,因为含硒酶对氧化还原稳态起关键作用。这种增加的摄入硒动力可能会覆盖小尺寸纳米硒的优势, 从而消除尺寸效应。当含硒酶被饱和,硒摄入机制可能下调,相应的纳米硒的尺寸作用可能会重新出现。为了证实该假设,给予硒缺乏小鼠36 nm90 nm两种尺寸超营养 剂量纳米硒,通过单剂量模式和短期模式考察。在这些研究条件下,纳米硒对硒积累和诱导脱毒酶谷胱甘肽硫转移酶显示出尺寸效应。在总共18个比较指标中,15个指标 体现出尺寸效应。进一步发现硒积累的尺寸效应比诱导谷胱甘肽硫转移酶的尺寸效应更突出。谷胱甘肽硫转移酶严格受转录和翻译控制,它的增加通常不超过3倍,而硒积 累并不受到严格控制。本研究中,谷胱甘肽硫转移酶已达到或接近于饱和,但肝硒远没达到饱和,因此我们的结果建议测试的生物指标的饱和特征对纳米硒的尺寸效应有 影响。因为谷胱甘肽硫转移酶和小分子硒积累与硒防癌作用相关,我们的结果也建议小尺寸纳米硒作为防癌剂可能会更有效。 本篇文章来源于 纳米硒中文网|www.nano-se.com ,转载请保留此信息!

浏览 (328) | 评论 (0) | 评分(0) | 支持(0) | 反对(0) | 发布人:纳米硒
将本文加入收藏夹
文章搜索
本月人气榜
脚注信息

提示:本站信息仅供参考,不能作为诊断及医疗的依据;请谨慎参阅,本站不承担由此引起的法律责任。
本网站敬告网民:身体若有不适,请及时到医院就诊。

Copyright © 2017 上海四通纳米技术港有限公司, All Rights Reserved