转基因斑马鱼在镉免疫毒性研究中的应用

Use of transgenic zebrafish in the study of cadmium immunotoxicity

为开发转基因斑马鱼技术在环境污染物免疫毒性研究中的应用,以转基因斑马鱼Tg(lysC:DsRed2)-Lyz fish为模型,利用斑马鱼胚胎发育技术和定量实时RT-PCR技术,探讨了Cd对斑马鱼仔鱼的免疫毒性及其作用机制。结果表明,0.01μmol·L^-1CdCl2即可显著抑制转基因斑马鱼胚胎的孵化(P=0.013),当暴露浓度增大到0.1μmol·L^-1时,斑马鱼胚胎24 h血流障碍和52 h孵化抑制这两个毒性效应都大幅增强,且剂量-效应关系显著。0.1μmol·L^-1CdCl2使得溶菌酶(lysozyme C,lyz)标记的斑马鱼仔鱼体内中性粒细胞数量增多,且趋向肝脏部位聚集。免疫毒性的作用机制与斑马鱼仔鱼体内金属硫蛋白相关基因(dMT)和炎症相关基因(serp、tnf)表达的诱导,以及癌症抑制相关基因(ccgn1、chk2、p53)表达的抑制有相关性。研究表明,转基因斑马鱼Tg(lysC:DsRed2)在重金属污染物免疫毒性评价中具有重要意义。

To use transgenic zebrafish in research on the immunotoxicity of environmental pollutants, transgenic zebrafish Tg(lysC:DsRed2)-Lyz fish was modelled, and zebrafish embryo development technology and quantitative real-time RT-PCR(Reverse Transcription-Polymerase Chain Reaction)technology were carried out in this study. The immunotoxicity of cadmium and its toxic mechanism were discussed. The results showed that the incubation of transgenic zebrafish embryos could be significantly inhibited by 0.01 μmol·L^-1 CdCl2(P=0.013). When the exposure concentration increased to 0.1 μmol·L^-1, 24 h blood flow disorder and 52 h hatch inhibition were both greatly enhanced in the fish embryo, and these toxic effects were significantly dose dependent. The level of neutrophils that were labelled with lysozyme(lysozyme C, lyz)in zebrafish larvae was increased upon 0.01 μmol·L^-1 CdCl2 exposure, and the neutrophils tended to aggregate in the fish liver. The mechanism of immunotoxicity was related to the induction of the expression of the metallothionein related gene(dMT)and inflammation related genes(serp, tnf), and the inhibition of the expression of cancer related genes(ccgn1, chk2, p53). Therefore, the transgenic zebrafish Tg(lysC:DsRed2)-Lyz fish could play important roles in the evaluation of the immunotoxicity of heavy metal pollutants.