摘要:
随着纳米技术的发展,纳米材料在生物医药以及化工中已得到广泛应用。作为一类新型材料,其安全性也日益受到人们的高度关注。为探索氧化锌(ZnO)纳米粒子对小鼠视网膜光感受器细胞的毒性作用,本文通过MTT、荧光染色、流式细胞术、实时荧光定量PCR和酶联免疫吸附试验(ELISA)等技术,分别对经不同浓度ZnO纳米粒子处理的小鼠光感受器细胞活性、活性氧水平、锰超氧化物歧化酶(MnSOD)的基因和蛋白表达及活性进行了检测。结果表明,ZnO纳米粒子可通过诱导细胞线粒体产生过多的活性氧,降低线粒体膜电位,导致小鼠视网膜光感受器细胞损伤;ZnO纳米粒子能显著减少MnSOD在mRNA和蛋白质水平的表达,降低MnSOD活性,加剧氧化应激介导的细胞损伤。因此,氧化应激水平的提高导致了过量的活性氧产生及MnSOD表达和活性的下降,与ZnO纳米粒子引起的细胞毒性作用有关。
Abstract:
Nanomaterials have been widely used in areas of biology, pharmacy and chemical industry due to its rapid development. As a new type of material, the toxicity of nanomaterials is also attracting enormous attention. In the present study, the effects of ZnO nanoparticles (NPs) on murine photoreceptor cell viability and on the expression and activity of MnSOD were investigated by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, fluorescent analysis, flow cytometry, quantitative real-time PCR and enzyme-linked immunosorbent assay (ELISA) techniques. ZnO NPs exhibited high cytotoxicity on the target cells in concentration- and time-dependent manners. ZnO NPs elevated intracellular levels of reactive oxygen species (ROS) and collapsed the mitochondrial membrane potential, thus leading to murine photoreceptor cell damage. Moreover, ZnO NPs significantly reduced the expression of MnSOD at both mRNA and protein levels, attenuated its activity, and further aggravated the oxidative stress-mediated cell damages. Overall, ZnO NPs-induced cytotoxicity on murine photoreceptor cells was closely associated with elevated levels of oxidative stress via the overproduction of ROS and decreased expression and activity of MnSOD.