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目的 通过探讨螯合剂与金属硫蛋白(MT)竞争结合铀(U)(VI)的作用,建立铀促排螯合剂体外筛选的新方法.方法 采用竞争ELISA法,96孔酶标板经MT抗原包被、U(VI)或Zn2+预处理、螯合剂(CBMIDA-CaNa2、BPCBG和DTPA-CaNa3)处理、MT抗体免疫结合、HRP偶联二抗结合及OPD显色反应后,在波长490 nm处检测吸光度值以评价螯合剂与MT竞争结合U(VI)、Zn2+的能力.结果 本反应体系的吸光度值随MT质量浓度和MT抗体浓度增加而增加,其中最佳MT抗原包被浓度和MT抗体浓度均为2μg/mL.与Zn2+的作用相似,U(VI)亦可使反应体系的吸光度值随其浓度增加而降低,其中最佳U(VI)和Zn2+浓度均为300μg/mL.加入CBMIDA-CaNa2和BPCBG则能明显提高U(VI)处理体系的吸光度值,CBMIDA-CaNa2的作用强于BPCBG,而DTPA-CaNa3则无明显作用;各螯合剂与MT竞争结合U(VI)能力的强弱顺序与以往细胞和动物U(VI)促排实验的结果相吻合.这3种螯合剂对Zn2+处理体系的吸光度值均无明显影响.结论 CBMIDA-CaNa2和BPCBG能有效竞争结合于MT上的U(VI),DTPA-CaNa3无明显作用,竞争ELISA法可作为体外筛选U(VI)促排螯合剂的方法,具有简便、快速和高通量的优势.“,”Objective To establish a new method for the in vitro screening of U (Ⅵ) decorporation agents by exploring the competitive combination with uranium (Ⅵ) between chelating agent and metallothionein (MT). Methods Competitive enzyme-linked immunosorbent assay (ELISA) was developed to detect the competitive ability of chelating agents to mobilize the U (Ⅵ) and Zn2+ binding to MT. MT antigen was coated on the surface of well of 96-well plates and then pretreated with U (Ⅵ) or Zn2+ and then individually treated with chelating agents of CBMIDA-CaNa2, BPCBG and DTPA-CaNa3 followed by reacted with MT antibody and the secondary antibody linked with horseradish peroxidase (HRP) enzyme. The absorption values were detected by spectrophotometry at 490 nm after the chromogenic reaction of OPD. Results The absorption values of this testing system increased with higher concentrations of coating MT and MT antibody, and the optimal concentration of coating MT and MT antibody were both 2 μg/mL. Similar to the effects of Zn2+, U (Ⅵ) treatment also reduced the absorption values of testing system, with the increase of U (Ⅵ) and Zn2+ concentration, and the optimal concentration of U (Ⅵ) and Zn2+ were both 300 μg/mL. Treatment with CBMIDA-CaNa2 and BPCBG significantly increased the absorption values of U (Ⅵ) -treated testing system, and effects of CBMIDA-CaNa2 were higher than that of BPCBG. DTPA-CaNa3 treatment had no effects on the absorption values of U (Ⅵ) -treated testing system. Importantly, the order of competitive ability of chelating agents to mobilize the U (Ⅵ) binding to MT was consistent with the results of previous in vitro cell culture and in vivo animal decorporation experiments for U (Ⅵ). In addition, treatment with the above chelating agents had no effects on the absorption values of Zn2+-treated testing system. Conclusion CBMIDA-CaNa2 and BPCBG can chelate U (Ⅵ) with MT, and the competitive chelation ability of CBMIDA-CaNa2 for U (Ⅵ) binding to MT is better than that of BPCBG while DTPA-CaNa3 has no obvious effect. This competitive ELISA assay can be used as a screening method for U (Ⅵ) decorporation agents in vitro which is simple, quick and high throughput.