纳米TiO_2和ZnO对杜氏盐藻氧化损伤机理的研究  

The Mechanism of Oxidative Damage on the Dunaliella Salina under nTiO_2 and nZnO

作　　者：周占清[1] 陈晓菲[1] 赵群芬[1] 

机构地区：[1]宁波大学海洋学院,浙江宁波315211

出　　处：《生物物理学报》2013年第12期925-936,共12页Acta Biophysica Sinica

基　　金：宁波大学学科基金项目(xkl1342)~~

摘　　要：作者分别研究了半致死浓度的纳米TiO2（nTi02）（50mg／L）和纳米ZnO（nZnO）（5mg／L）对杜氏盐藻超微结构、细胞活性、胞内ROS，以及HSP70和Mn．SOD基因表达的影响。结果显示：nTiO2和nZnO均能进入杜氏盐藻细胞内，使淀粉核和淀粉粒被氧化变黑、类曩体严重氧化断裂、线粒体肿大、细胞膜疏松．并使部分细胞器和细胞核发生了凋亡。FDA—PI双染显示，6～36h内，胁迫组杜氏盐藻细胞活性均被明显抑制（P〈0．05），到72h时，细胞活性完全恢复；48h时，ROS对应的荧光值最高，且HSP70和Mn-SOD基因的表达在48h时均明显上调（P〈0．01）。由此推断，nTiO2和nZnO对杜氏盐藻的氧化损伤可能是由于氧化应激性引起了细胞内ROS的升高，使蛋白质变性、酶失活、基因表达受阻、细胞核凋亡、细胞器解体等，此外，nTiO2和nZnO的吸附性可对细胞产生损伤，但随着被吸附物的增多，其吸附能力下降的同时，也会导致纳米材料的光催化性能下降．从而降低对细胞的毒性效应。The effects of nTiO2 （median lethal dose, 50 mg/L） and nZnO （median lethal dose, 5 mg/L） on the ultrastructures, cellular activity, intracellular ROS and the expression of HSP70 and Mn-SOD of Dunaliella salina were studied. It revealed that these two nano-materials could enter into the cells, and made the starch grain and pyrenoid black, the thylakoid-membranes fractured, the mitochondrion swelling, the plasmalemma slacking, the nucleus and part of organelles generating apoptosis. FDA-PI double staining fluorescent images showed that, compared with the control group, the cellular activities of groups stressed by nTiO2 and nZnO for 6~36 h were significantly inhibited （P〈0.05）, and completely restored in groups which were stressed for 72 h. The corresponding fluorescence values of ROS were 45.31±12.79 and 64.27±0.93 when stressed by nTiO2 and nZnO for 48 h, respectively. The expression of genes HSP70 and Mn-SOD of the stressed groups increased obviously at 48 h （P〈0.01） compared with the control group. It suggested that, the possible mechanism of oxidative damage of nZnO and nTiO2 to the Dunaliella salina is caused by the increase of ROS, which makes proteins denaturated, enzymes inactivated, genetic expressions blocked, organelles disintegrated and the nucleuses go into apoptosis etc. In addition, the adsorptivity of nTiO2 and nZnO may cause damage to cells. However, with the increasing of the adsorbate, the adsorbability would fall down, and at the same time, it can also lead to the decline of nano-materiars light catalytic performance, thereby decreases the cellular toxic effectivity.

关 键 词：nTiO2 nZnO 杜氏盐藻 氧化损伤机理 

分 类 号：Q89[生物学]