Wang Yurong, Cui Haiyan, Zhou Jiaping, Li Fengjuan, Wang Jinju, Chen Mianhua, Liu Qingdai
Key Laboratory of Food Nutrition and Safety, Ministry of Education, School of Food Engineering and Biotechnology, Tianjin University of Science and Technology, No. 29, 13th Avenue, TEDA, Tianjin, 300457, China,
Environ Sci Pollut Res Int. 2015 Apr;22(7):5519-30. doi: 10.1007/s11356-014-3717-7. Epub 2014 Oct 24.
Concerns about the risk of titanium dioxide nanoparticles (TiO2 NPs) to human health and environment are gradually increasing due to their wide range of applications. In this study, cytotoxicity, DNA damage, and apoptosis induced by TiO2 NPs (5 nm) in A549 cells were investigated. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays revealed the time- and concentration-dependent cytotoxic effects of TiO2 NPs in a concentration range of 50 to 200 μg/mL. A statistically significant (p < 0.05) induction in DNA damage was observed by the comet assay in cells exposed to 50 to 200 μg/mL TiO2 NPs for 48 h. A significant (p < 0.05) induction in micronucleus formation determined by 4,6-diamino-2-phenylindole (DAPI) staining was also observed at the above concentrations. Typical apoptotic morphological feature and apoptotic bodies in A549 cells induced by TiO2 NPs at the above concentrations were observed by scanning electron micrographs. Flow cytometric analysis demonstrated that the cells treated with TiO2 NPs at concentrations of 100 and 200 μg/mL showed a significant G2/M phase arrest and a significant increased proportion of apoptotic cells. TiO2 NPs also disrupted the mitochondrial membrane potential evaluated by rhodamine 123 staining. Further analysis by quantitative real-time PCR (qRT-PCR) indicated that the expression of caspase-3 and caspase-9 messenger RNA (mRNA) was increased significantly at the concentrations of 100 and 200 μg/mL TiO2 NPs for 48 h. Taken together, these findings suggest that TiO2 NPs can inhibit A549 cell proliferation, cause DNA damage, and induce apoptosis via a mechanism primarily involving the activation of the intrinsic mitochondrial pathway. The assay data provide strong evidence that TiO2 NPs can induce cytotoxicity, significant DNA damage, and apoptosis of A549 cells, suggesting that exposure to TiO2 NPs could cause cell injury and be hazardous to health.
由于二氧化钛纳米颗粒（TiO₂ NPs）的广泛应用，人们对其对人类健康和环境风险的担忧正逐渐增加。在本研究中，对5纳米的TiO₂ NPs诱导A549细胞的细胞毒性、DNA损伤和凋亡进行了研究。3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐（MTT）试验揭示了在50至200μg/mL浓度范围内TiO₂ NPs的时间和浓度依赖性细胞毒性作用。彗星试验显示，暴露于50至200μg/mL TiO₂ NPs 48小时的细胞中，DNA损伤有统计学意义（p＜0.05）的诱导。在上述浓度下，通过4,6-二氨基-2-苯基吲哚（DAPI）染色测定的微核形成也有显著（p＜0.05）的诱导。通过扫描电子显微镜观察到上述浓度的TiO₂ NPs诱导的A549细胞中的典型凋亡形态特征和凋亡小体。流式细胞术分析表明，用100和200μg/mL浓度的TiO₂ NPs处理的细胞显示出显著的G2/M期阻滞和凋亡细胞比例显著增加。TiO₂ NPs还破坏了通过罗丹明123染色评估的线粒体膜电位。通过定量实时PCR（qRT-PCR）进一步分析表明，在100和200μg/mL TiO₂ NPs浓度下处理48小时，半胱天冬酶-3和半胱天冬酶-9信使核糖核酸（mRNA）的表达显著增加。综上所述，这些发现表明TiO₂ NPs可抑制A549细胞增殖，导致DNA损伤，并通过主要涉及激活内源性线粒体途径的机制诱导凋亡。试验数据提供了有力证据，证明TiO₂ NPs可诱导A549细胞的细胞毒性、显著的DNA损伤和凋亡，表明暴露于TiO₂ NPs可能导致细胞损伤并对健康有害。
