中文摘要：

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.

英文摘要：

A comparison was made for the size-dependent DNA damage induced by both nano dioxide manganese particles（Nano-MnO2）and normal size dioxide manganese particles（Nor-MnO2）. Hela cells were exposed to different concentrations of both Nano-MnO2 and Nor-MnO2 （0, 100, 200, 400μg·mL^-1）, respectively. The DNA damage of Hela cells was measured by the comet assay after 24h MnO2-cultivated. Results showed that the Tail DNA% and Tail Moment were both significantly increased after exposed to both Nano-MnO2 and Nor-MnO2 when compared with the control（p〈0.01 for all）. At the same concentration level, Nano-MnO2 could induce more serious DNA damage than Nor-MnO2（p〈0.01 for all）. The results suggested that Nano-MnO2 should have more serious toxic effect regarding to DNA damage of the Hela cells than that of Nor-MnO2.