多壁碳纳米管对DNA的体外氧化损伤研究

The oxidative DNA damage in vitro induced by multi-walled carbon nanotubes

目的观察多壁碳纳米管(multi-walled nanotubes,MWCNTs)对DNA超螺旋构型的影响和氧化损伤。方法选择不同浓度多壁碳纳米管(50～500μg/ml)与pBR322质粒DNA及小牛胸腺DNA(ct-DNA)作用,采用质粒DNA凝胶电泳和圆二色谱分析。结果多壁碳纳米管能够引起pBR322质粒DNA的损伤,其DNA损伤率(16%～42%)呈剂量-反应关系,多壁碳纳米管高浓度(500μg/ml)时DNA降解成线性条带。在活性氧清除剂-维生素C的作用下,DNA损伤率可由45.24%降低到18.64%。多壁碳纳米管可削弱DNA碱基之间的堆积作用,导致DNA解链。结论多壁碳纳米管可通过活性氧介导DNA损伤。

Objective To evaluate the impact of multi-walled carbon nanotube （MWCNTs） on supercoiling structure of DNA and oxidative DNA damage induced in vitro. Methods The gel electrophoresis on supercoiled pBR322 plasmid DNA and the circular dichroism （CD） analysis in vitro were used on the treatment of MWCNTs at 50-500 μg/ml. Results MWCNTs could induce the damage of pBR322 plasmid DNA in a dose-dependent manner. Supplementation with Vitamin C, which was the scavenger of reactive oxygen species （ ROS）, caused a significant decline in the rate of DNA damage from 45.24% to 18.64%. Moreover, MWCNTs could undermine the power of base stacking of supercoiled DNA and make conformational change of ct-DNA from folded compact state to elongated coil state by interacting with ct-DNA. Conclusion This resuh demonstrated that the MWCNTs could induce DNA damage possibly mediated by ROS.