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[目的]探讨不同浓度纳米二氧化钛(nanosized titanium dioxide,Nano-TiO2)颗粒对人肺上皮细胞(A549细胞)增殖的影响及其可能机制。[方法]采用不同粒径(5、10和40 nm)和浓度(0、0.125、0.25、0.5、1、2、4、8、16 mg/L)的Nano-TiO2处理A549细胞24 h,用四甲基偶氮唑盐(MTT)法和细胞计数法观察Nano-TiO2对细胞增殖的影响;用流式细胞术检测Nano-TiO2对细胞凋亡的影响;用蛋白质免疫印记法(Western Blot)测定Nano-TiO2对细胞外调节蛋白激酶(extracellular-receptor kinase,ERK)的影响。并采用ERK特异性抑制剂PD98059(20μmol/L)对细胞进行预处理30 min后,MTT法观察ERK抑制剂对低浓度Nano-TiO2(0.5 mg/L)调节细胞增殖的影响。[结果]不同粒径的Nano-TiO2均表现出较低浓度(≤4 mg/L)促进细胞增殖,较高浓度(≥8 mg/L)抑制细胞活力的作用,而更高浓度Nano-TiO2(16 mg/L)可引起细胞凋亡的发生。进一步研究发现,低浓度Nano-TiO2(0.5 mg/L)可引起细胞磷酸化ERK表达增强,ERK抑制剂PD98059可明显抑制低浓度Nano-TiO2(0.5 mg/L)的促细胞增殖作用。[结论]低浓度Nano-TiO2可通过激活ERK促进细胞增殖,较高浓度Nano-TiO2则引发细胞凋亡发挥其抑制细胞活力的作用;不同粒径Nano-TiO2的效应之间没有明显差异。
[Objective] To investigate the effects of different concentrations of nanosized titanium dioxide (Nano-TiO2) particles on the proliferation of human lung epithelial cells (A549 cells) and its possible mechanism. [Method] A549 cells were treated with Nano-TiO2 with different particle size (5,10 and 40 nm) and concentration (0,0.125,0.25,0.5,1,2,4,8 and 16 mg / L) for 24 h. The effect of Nano-TiO2 on cell proliferation was observed by MTT method and cell counting method. The effect of Nano-TiO2 on apoptosis was detected by flow cytometry. The protein expression was detected by Western Blot, To determine the effect of Nano-TiO2 on extracellular-receptor kinase (ERK). The cells were pre-treated with ERK inhibitor PD98059 (20μmol / L) for 30 min. The effect of ERK inhibitor on the proliferation of Nano-TiO2 (0.5 mg / L) cells was observed by MTT assay. [Result] Nano-TiO2 with different particle size showed the effects of lower concentration (≤4 mg / L) to promote cell proliferation and higher concentration (≥8 mg / L) to inhibit cell viability. Higher concentrations of Nano-TiO2 (16 mg / L) can cause apoptosis. Further study showed that low concentration of Nano-TiO2 (0.5 mg / L) could induce the phosphorylation of ERK, and the ERK inhibitor PD98059 could significantly inhibit the proliferation of Nano-TiO2 (0.5 mg / L) [Conclusion] Low concentration of Nano-TiO2 can promote cell proliferation by activating ERK. Higher concentration of Nano-TiO2 can induce cell apoptosis and exert its inhibitory effect on cell viability. There is no significant difference between Nano-TiO2 with different particle size.