Institute of Ophthalmological Research, Renmin Hospital of Wuhan University, 430060 Wuhan, China.
J Biomed Nanotechnol. 2010 Jun;6(3):260-71. doi: 10.1166/jbn.2010.1126.
In the study on the interactions of carbon nanotubes with living cells, the cell membrane deserves particular attention as it provides the first interface to initiate CNTs-cell interactions. In the present study, the inhibiting effect of multiwalled carbon nanotubes on the extrusion of fluorescein in human glioma cells was demonstrated using two procedures. To provide clues to explanation of this effect, intracellular glutathione content and reactive oxygen species production were determined as fluorescein is a specific substrate of cell membrane multidrug resistance-related protein whose transport activity requires glutathione which can be depleted under oxidative stress. The plasma membrane potential was also probed as the susceptibility of fluorescein efflux to modulation of the plasma membrane potential has been documented. Results showed a remarkable decrease in cellular glutathione level as well as an increase in reactive oxygen species production. Probe staining also indicated decreased plasma membrane potential. The data suggested that multiwalled carbon nanotubes may affect the transport activity of cell membrane multidrug resistance-related protein through reduction of intracellular glutathione content. Hypopolarization of the plasma membrane may also contribute to MWCNTs' effect. Implications of these findings are discussed.
在研究碳纳米管与活细胞的相互作用时，细胞膜尤其值得关注，因为它提供了与 CNTs 细胞相互作用的第一个接口。在本研究中，使用两种程序证明了多壁碳纳米管对人神经胶质瘤细胞中荧光素挤出的抑制作用。为了解释这种效应，测定了细胞内谷胱甘肽含量和活性氧的产生，因为荧光素是细胞膜多药耐药相关蛋白的特异性底物，其转运活性需要谷胱甘肽，而谷胱甘肽在氧化应激下会被耗尽。还探测了质膜电位，因为已经证明荧光素外排对质膜电位的调节敏感性。结果表明细胞内谷胱甘肽水平显著降低，活性氧的产生增加。探针染色也表明质膜电位降低。数据表明，多壁碳纳米管可能通过降低细胞内谷胱甘肽含量来影响细胞膜多药耐药相关蛋白的转运活性。质膜的去极化也可能有助于 MWCNTs 的作用。讨论了这些发现的意义。
