为了观察二氧化锰颗粒物所致的尺度依赖性DNA损伤作用,将纳米尺度二氧化锰颗粒物(Nano-MnO2)和常规尺度二氧化锰颗粒物(Nor-MnO2)所致的DNA损伤进行了对比研究.将Hela细胞分别暴露于不同浓度(0、100、200、400μg·mL-1)的Nano-MnO2和Nor-MnO2中,染毒24h,采用彗星实验检测Hela细胞的DNA损伤水平.结果表明:与对照组相比,Nano-MnO2和Nor-MnO2均可使彗尾DNA百分比(TailDNA%)和尾矩(TailMoment)显著增加(p<0.01);而在同一浓度水平上,Nano-MnO2所致的DNA损伤则比Nor-MnO2所致的DNA损伤更为严重(p<0.01).结果提示:二氧化锰颗粒对Hela细胞DNA损伤具有尺度依赖性毒作用,纳米尺度比常规尺度二氧化锰颗粒毒作用更强烈. To observe the scale-dependent DNA damage caused by manganese dioxide particles, DNA damage caused by nano-sized manganese dioxide particles (Nano-MnO2) and conventional-scale manganese dioxide particles (Nor-MnO2) was compared. The Hela cells were exposed to Nano-MnO2 and Nor-MnO2 at different concentrations (0, 100, 200 and 400μg · mL-1) respectively, and the DNA damage levels of Hela cells were detected by comet assay 24h after exposure.Results showed that Compared with the control group, both Nano-MnO2 and Nor-MnO2 significantly increased the percentage of tail DNA and TailMoment (p <0.01); while at the same concentration, Nano-MnO2 induced DNA damage was more severe than DNA damage caused by Nor-MnO2 (p <0.01) .The results suggest that manganese dioxide particles have a scale-dependent toxic effect on DNA damage of Hela cells, the nano-scale is more toxic than the conventional standard manganese dioxide particles More powerful.