纳米氧化硅对RAW264.7细胞的DNA损伤作用  

DNA-damage in RAW264.7 cells exposed to different sizes of silica nanoparticles

作　　者：杨红[1] 吴秋云[1] 劳灿山 李明月[1] 李文超[1] 

机构地区：[1]东南大学公共卫生学院环境医学工程教育部重点实验室,江苏南京210009

出　　处：《癌变．畸变．突变》2016年第4期249-254,共6页Carcinogenesis,Teratogenesis & Mutagenesis

基　　金：国家自然科学基金面上项目(81273046);江苏省预防医学科研课题(Y2012039)

摘　　要：目的:研究纳米氧化硅(SiO_2)对小鼠RAW264.7细胞的DNA损伤作用,探讨其可能的毒作用机制。方法:分别采用浓度为31.25、125、500μg/m L的两种纳米SiO_2(平均粒径分别为20、60 nm)和500μg/m L的微米SiO_2粒子悬液对RAW264.7细胞染毒24 h,彗星试验检测细胞DNA单链断裂情况,CASP软件分析彗星图像,观察指标为彗星率(r_(彗星))、尾长(TL)、尾部DNA百分率(r_(尾部DNA))和OT尾矩(OTM);分别用硝酸还原酶法、TBA法、Fenton法、黄嘌呤氧化酸法、钼酸法、考马斯亮兰法测定各组染毒细胞匀浆上清液中细胞氧化应激指标丙二醛(MDA)、羟自由基(·OH)、超氧阴离子(O_2)、过氧化氢(H2 O2)、一氧化氮(NO)和蛋白含量。结果:与阴性对照组比较,500μg/m L微米SiO_2染毒组和125、500μg/m L的两种纳米SiO_2染毒RAW264.7细胞时,r_(彗星)、TL、r_(尾部DNA)、OTM均升高(P<0.01);且500μg/m L微米SiO_2组的r_(彗星)、r_(尾部DNA)、OTM高于同浓度两个纳米SiO_2组(P<0.01)。两种纳米SiO_2和微米SiO_2染毒细胞内脂质过氧化产物MDA、OH、O_2、NO及H_2O_2的水平均高于阴性对照组(P<0.01)。结论:两种纳米SiO_2与微米SiO_2均可引起RAW264.7细胞DNA断裂和氧化损伤,氧化应激自由基的大量产生在DNA损伤过程中可能起到一定的作用。OBJECTIVE： RAW264.7 cells were exposed to different doses ofsilica nanoparticles and micronsilicon dioxide （SiO ）,and induction of DNA damage was investigated. METHODS：RAW264.7 cells were treated with 220 nm,60 nm silica nanoparticles at dosage of 31.25-500 μg/mL and micron SiO at dosage of 500 μg/mL for 24 h. DNA 2single-strand break was detected by the Comet single cell gel electrophoresis （SCGE） and all the indexes of the assay：rate of comet （r ）,tail length （TL） of DNA,rate of tail DNA （r ）,and Olive tail moment （OTM） were analyzed by the comet tail DNA· Comet Assay Software Project （CASP）. In addition,levels of malondialdehyde （MDA）,hydroxyl radicals （ OH）,-·superoxide anion radical （O ）,hydrogen peroxide （H O ） and nitric oxide （NO） in homogenate supernatantfrom treatedcells 2 2 2were measured. RESULTS：r ,TL,r and OTM induced by microsized SiO were significantly increased compared comet tail DNA 2with the negative control at the concentration of 500 μg/mL （P〈0.01）. Cells exposed to 125 and 500 μg/mL of the two kindsof silica nanoparticles showed a distinct increase of r ,TL,r and OTM compared with the negative control comet tail DNA（P〈0.01）. r ,r and OTM caused by microsized SiO were significantly increased compared with the silica comet tail DNA 2nanoparticles groups（P〈0.01） at the same concentrations. The increase of lipid peroxidation products of MDA and free· -· radicals of OH,O ,H O and NO were in different degrees the result from silica nanoparticle and micron SiO in 2222comparison t o t he negative control. CONCLUSION：Both silica nanoparticle and microsized SiO can cause DNA single- 2strand break and oxidative injury in RAW264.7 cells. The generation of free radicals of oxidative stress may have played arole in induction of DNA-damage.

关 键 词：纳米SIO2 RAW264.7细胞 自由基 遗传毒性 单细胞凝胶电泳 

分 类 号：Q355[生物学—遗传学]