Wang Jing J, Sanderson Barbara J S, Wang He
Department of Public Health, Level 9, 10 Pulteney Street, University of Adelaide, SA 5005, Australia.
Mutat Res. 2007 Apr 2;628(2):99-106. doi: 10.1016/j.mrgentox.2006.12.003. Epub 2006 Dec 15.
Titanium dioxide is frequently used in the production of paints, paper, plastics, welding rod-coating material, and cosmetics, because of its low toxicity. However, recent studies have shown that nano-sized or ultrafine TiO(2) (UF-TiO(2)) (<100 nm in diameter) can generate pulmonary fibrosis and lung tumor in rats. Cytotoxicity induced by UF-TiO(2) in rat lung alveolar macrophages was also observed. This generates great concern about the possible adverse effects of UF-TiO(2) for humans. The cytotoxicity and genotoxicity of UF-TiO(2) were investigated using the methyl tetrazolium cytotoxicity (MTT) assay, the population growth assay, the apoptosis assay by flow cytometry, the cytokinesis block micronucleus (CBMN) assay, the comet assay, and the hypoxanthine-guanine phosphoribosyltransferase (HPRT) gene mutation assay. WIL2-NS cells were incubated for 6, 24 and 48 h with 0, 26, 65 and 130 microg/ml UF-TiO(2). Significant decreases in viability were seen in the MTT assay at higher doses; for example, 61, 7 and 2% relative viability at 130 microg/ml for 6, 24 and 48-h exposure (P<0.01). A dose-dependent relationship was observed, while a time-dependent relationship was seen only at the highest dose (130 microg/ml) after exposure for 24 and 48 h. Treatment with 130 microg/ml UF-TiO(2) induced approximately 2.5-fold increases in the frequency of micronucleated binucleated cells (P<0.01). In addition, a significant reduction in the cytokinesis block proliferation index was observed by the CBMN assay (P<0.05). In the comet assay, treatment with 65 microg/ml UF-TiO(2) induced approximately 5-fold increases in olive tail moment (P<0.05). In the HPRT mutation assay, treatment with 130 microg/ml UF-TiO(2) induced approximately 2.5-fold increases in the mutation frequency (P<0.05). The results of this study indicate that UF-TiO(2) can cause genotoxicity and cytotoxicity in cultured human cells.
由于二氧化钛毒性较低，它常用于涂料、纸张、塑料、焊条涂层材料及化妆品的生产。然而，最近的研究表明，纳米级或超细微的TiO₂（UF-TiO₂）（直径<100纳米）可在大鼠体内引发肺纤维化和肺部肿瘤。还观察到UF-TiO₂对大鼠肺泡巨噬细胞具有细胞毒性。这引发了人们对UF-TiO₂可能对人类产生的不良影响的极大关注。使用甲基四氮唑细胞毒性（MTT）测定法、群体生长测定法、流式细胞术凋亡测定法、胞质分裂阻滞微核（CBMN）测定法、彗星试验及次黄嘌呤-鸟嘌呤磷酸核糖转移酶（HPRT）基因突变测定法，对UF-TiO₂的细胞毒性和遗传毒性进行了研究。将WIL2-NS细胞分别与0、26、65和130微克/毫升的UF-TiO₂孵育6、24和48小时。在MTT测定中，较高剂量时细胞活力显著下降；例如，在130微克/毫升剂量下，暴露6、24和48小时后的相对细胞活力分别为61%、7%和2%（P<0.01）。观察到剂量依赖性关系，而仅在最高剂量（130微克/毫升）暴露24和48小时后观察到时间依赖性关系。用130微克/毫升UF-TiO₂处理可使微核双核细胞频率增加约2.5倍（P<0.01）。此外，通过CBMN测定观察到胞质分裂阻滞增殖指数显著降低（P<0.05）。在彗星试验中，用65微克/毫升UF-TiO₂处理可使橄榄尾矩增加约5倍（P<0.05）。在HPRT突变试验中，用130微克/毫升UF-TiO₂处理可使突变频率增加约2.5倍（P<0.05）。本研究结果表明，UF-TiO₂可在培养的人细胞中引起遗传毒性和细胞毒性。
