三氯生对青海弧菌Q67和人乳腺癌细胞MCF-7的时间毒性

三氯生(triclosan,TCS)是一种广谱性抗菌剂,2005年欧盟水框架指令将TCS列为一种新型污染物。目前对TCS的研究局限于急性毒性实验,关于TCS毒性随时间的变化以及不同溶解状态下TCS的毒性差异的研究却鲜有报道。应用以96孔微板为暴露反应载体的微板毒性分析法,添加氢氧化钠(NaOH)或使用二甲亚砜(DMSO)作为助溶剂溶解TCS,分别测定其对青海弧菌Q67的相对发光抑制毒性(15min急性毒性和时间毒性)和对人乳腺癌细胞MCF-7在不同暴露时间(24、48和72h)内的细胞增殖抑制毒性。Q67的急性毒性实验结果表明,碱性条件下TCS的毒性(EC50=3.97(10-8mol.L-1)大于DMSO作为助溶剂时的毒性(EC50=1.68(10-4mol.L-1)。无论碱性条件还是DMSO助溶,TCS在不同暴露时间内对Q67的时间毒性没有明显差异。在不同暴露时间下MCF-7增殖抑制率实验中,DMSO作为助溶剂时,TCS的最高实验浓度为1.46(10-3mol.L-1,随着暴露时间的延长,抑制率在24、48和72h时分别为27.8%、44.2%和62.4%;碱性环境时TCS的最高实验浓度为1.39(10-6mol.L-1,随着暴露时间的延长,抑制率在24、48和72h时分别为20.2%、55.8%和73.9%。研究表明,在DMSO和NaOH作为助溶剂的条件下,TCS对MCF-7均存在时间毒性差异,并且NaOH碱性溶液中TCS对MCF-7的毒性远大于DMSO作为助溶剂时的毒性。

Time-dependent Toxicities of Triclosan to Vibrio qinghaiensis sp.-Q67 and Human Breast Cancer Cell MCF-7

A broad-spectrum antibacterial agent, triclosan (TCS) was listed in European Union Water Framework Directive (2005) as an emerging environmental pollutant. Until now, most studies focused on acute toxicity of TCS, however, few studies were performed on time-dependent toxicity of TCS and its toxicity in different solution systems. NaOH solution and dimethyl sulfoxide (DMSO) were used to dissolve TCS. Microplate toxicity analysis (MTA) was used to determine the acute (15 min exposure and time-dependent) luminescent inhibition toxicities of TCS to Vibrio qinghaiensis sp.-Q67 (Q67) and time-dependent proliferation inhibition toxicities to human breast cancer cell MCF-7 at different exposure times (24, 48 and 72 h). Results showed that the acute toxicity (EC₅₀ = 3.97×10^-8 mol·L^-1) of TCS to Q67 in DMSO is much higher than that (1.68×10^-4 mol·L^-1) in NaOH solution. In time-dependent toxicity assay, there was no time-dependent toxicity difference across difference time intervals for TCS in DMSO or NaOH solution. In MCF-7 proliferation inhibition assay, the inhibition ratio of the highest TCS concentration (1.46×10^-3 mol·L^-1) in DMSO was 27.8% for 24 h, 44.2% for 48 h, and 62.4% for 72 h exposure. The inhibition ratio of the highest TCS concentration (1.39×10^-6 mol·L^-1) in NaOH solution was 20.2% for 24 h, 55.8% for 48 h, and 73.9% for 72 h exposure. As a result, in MCF-7 proliferation inhibition ratio assay, there was significant time-dependent toxicity difference for TCS both in DMSO and NaOH solution, and the toxicity of TCS in NaOH solution was much higher than that in DMSO.