College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China.
College of Science, Northwest A&F University, Yangling 712100, China.
J Hazard Mater. 2016 Nov 15;318:650-662. doi: 10.1016/j.jhazmat.2016.07.049. Epub 2016 Jul 21.
Using Saccharomyces cerevisiae as an experimental model, the potential toxicological effects of oxidized multi-walled carbon nanotubes (MWCNTs) were investigated following exposure to 0-600mg/L for 24h. Results indicated that MWCNTs (>100mg/L) had adverse effects on the cell proliferation. MWCNTs were clearly visible in lysosome, vacuole, endosome, mitochondria, multivesicular body and localization in the perinuclear region. The uptake kinetics data demonstrated that the maximum MWCNTs content (209.61mg/g) was reached at 3h, and a steady state was reached after 18h. Based on the combined results of transmission electron microscope, endocytosis inhibition experiments and endocytosis-related genes (END3, END6, Sla2 and Rsp5) expression analysis, we elucidated MWCNTs uptake mechanism: (i) via a direct penetration of single MWCNTs; (ii) via endocytosis of single MWCNTs; and (iii) via endocytosis of MWCNTs aggregates. The percentage of apoptosis was significant increased at 600mg/L. The decrease of mitochondrial transmembrane potential and the leakage of cytochrome c shown dose-dependent manners. Interestingly, there was no significant increase of reactive oxygen species (ROS). The apoptosis-related genes (SOD1, SOD2, Yca1, Nma111 and Nuc1) were significant changed. These results obtained in our study demonstrated that oxidized MWCNTs induce Saccharomyces cerevisiae apoptosis via mitochondrial impairment pathway.
以酿酒酵母为实验模型，研究了暴露于 0-600mg/L 氧化多壁碳纳米管（MWCNTs）24 小时后的潜在毒理学效应。结果表明，MWCNTs（>100mg/L）对细胞增殖有不良影响。MWCNTs 在溶酶体、液泡、内体、线粒体、多泡体和核周区明显可见。摄取动力学数据表明，MWCNTs 的最大含量（209.61mg/g）在 3 小时达到，18 小时后达到稳定状态。基于透射电子显微镜、内吞作用抑制实验和内吞作用相关基因（END3、END6、Sla2 和 Rsp5）表达分析的综合结果，我们阐明了 MWCNTs 的摄取机制：（i）通过单根 MWCNTs 的直接穿透；（ii）通过单根 MWCNTs 的内吞作用；和（iii）通过 MWCNTs 聚集体的内吞作用。在 600mg/L 时，细胞凋亡的比例显著增加。线粒体跨膜电位的下降和细胞色素 c 的泄漏呈剂量依赖性方式。有趣的是，活性氧物种（ROS）没有显著增加。凋亡相关基因（SOD1、SOD2、Yca1、Nma111 和 Nuc1）发生显著变化。我们的研究结果表明，氧化 MWCNTs 通过线粒体损伤途径诱导酿酒酵母细胞凋亡。
