摘要
目的探讨纳米二氧化钛（TiO2）颗粒光催化活性对人表皮鳞状细胞癌细胞株A431的生长抑制效应及机制。方法单纯紫外线（主要波长为253．7nm，功率30w，光距30cm，照射时间15min）、不同浓度（100、200、300、400、500、600mg／L）纳米TiO2及纳米TiO2紫外线作用于A431细胞，采用噻唑蓝（MTY）法检测上述因素对A431细胞生长抑制率的影响；膜联蛋白V-异硫氰酸荧光素，碘化丙啶（AnnexinV—FITc倒）双染法检测A431细胞凋亡率；罗丹明123（Rh0123）染色法检测A431细胞线粒体跨膜电位的变化。采用SPSS13．0统计软件进行t检验和方差分析，组间比较采用SNK检验。结果实验干预24、48、72h后，100、200、300、400、500、600mg／L纳米TiO：＋紫外线组A431细胞的生长抑制率增高，且呈浓度依赖效应，3个时间点不同浓度组比较，F值分别为21．54、77．56、20．27，P值均〈0．05（n=6），SNK检验示各组间差异均有统计学意义；而不同浓度单纯纳米TiO：组细胞生长抑制率在3个时间点均无明显增高，差异均无统计学意义（P值均〉0．05）。纳米TiO2联合紫外线照射可诱导A431细胞发生凋亡，并降低A431细胞线粒体跨膜电位，100、200、400mg／L纳米Ti02＋紫外线组凋亡率分别为8．86％±0．22％、11．72％±0．29％、31．24％±0．78％，空白对照组为2．69％±0．28％，经方差分析，差异有统计学意义（F=256．61，P〈0．05，n=3）；以上3个浓度组线粒体跨膜电位总荧光强度值分别为758．48±15．42、676．60±14．35、557．71±13．12，空白对照组为2943．65±70．26，经方差分析，差异有统计学意义（F=208．57，P〈0．05，n=3），SNK检验示各组间差异均有统计学意义。结论纳米TiO2＋紫外线对A431细胞有生长抑制作用，并能诱导细胞凋亡，线粒体跨膜电位下降可能是其诱导细胞凋亡的机制之一；单纯纳米TiO2对A431细胞的生长无抑制作用。
Objective To evaluate the inhibitory effect of photocatalytic titanium dioxide （TiO2）on the growth of a human epidermal squamous cell carcinoma cell line A431 and its mechanism. Methods Cultured A431 cells were classified into various groups to remain untreated （blank control group）, be treated with different concentrations （100, 200, 300, 400, 500, 600 mg/L） of TiO2 nanoparticles alone or in combination with ultraviolet （UV, main wavelength 253.7 nm, power 30 W, distance 30 cm, exposure duration 15 min） irradiation. After additional culture for different durations, methyl thiazolyl tetrazolium （MTY） assay was performed to evaluate cell growth, annexin V-fluorescein isothiocyanate/propidium iodide （PI） double staining to observe cell apoptosis, and Rho123 staining to determine mitochondrial transmembrane potential. Statistical analysis was earried out using SPSS 13.0 software. Analysis of variance （AOV）, t test and Student-NewmanKeuls （SNK） test were performed to assess the differences in these parameters between these groups. Results The growth of A431 cells was inhibited by pretreatment with TiO2 nanoparticles followed by UV irradiation, and the inhibitory effect was enhanced as the dose of TiO2 nanoparticles increased. As AOV and SNK test showed, there were significant differences in the growth inhibition rate among A431 cells treated with different concentrations of TiO2 nanoparticles at the three time points （24, 48 and 72 hours） after UV irradiation （n = 6, F = 21.54, 77.56, 20.27, respectively, all P 〈 0.05）. No statistical inhibition was observed in the growth of A431 cells treated with TiO2 nanopartieles alone compared with untreated A431 cells （all P 〉 0.05）. Photocatalytie TiO2 nanoparticles also induced the apoptosis but decreased the mitochondrial transmembrane potential in A431 cells. In detail, theapoptosis rate was 8.86% ± 0.22%, 11.72% ± 0.29% and 31.24% ± 0.78% in A431 cells treated with Ti02 nanoparticles of 100, 200, 400 mg/L followed by UV irradiation, respectively, compared to 2.69% ± 0.28% in the blank control group （n = 3, F = 256.61, P 〈 0.05）. Decreased mitochondrial transmembrane potential （expressed as total fluorescence intensity） was observed in A431 cells treated with Ti02 nanoparticles of 100, 200, 400 mg/L followed by UV irradiation compared with blank control group （758.48 ± 15.42, 676.60 ± 14.35, 557.71 ± 13.12 vs. 2943.65 ± 70.26, F = 208.57, P 〈 0.05, n = 3）, and SNK test also revealed statistical differences between these groups. Conclusions Ti02 nanoparticles combined with UV can inhibit the growth of but induce the apoptosis in A431 cells, which may be associated with the reduction in mitoehondrial transmembrane potential in A431 cells, while Ti02 nanoparticles alone show no inhibitory effect on the growth of A431 cells.
出处
《中华皮肤科杂志》
CAS
CSCD
北大核心
2012年第12期843-846,共4页
Chinese Journal of Dermatology
基金
国家自然科学基金（81172590）
陕西省科技计划（2010K14-02-18）
关键词
癌
鳞状细胞
纳米复合物
细胞系
肿瘤
紫外线
细胞凋亡
膜电位
线粒体
Carcinoma, squamous cell
Nanocomposites
Cell line, tumor
Ultraviolet rays
Apoptosis
Membrane potential, mitochondrial
