镉暴露对斑马鱼胚胎发育的毒性效应研究

Toxic Effects of Cadmium Exposure on Zebrafish Embryo Development

  • 摘要: 镉是一种具有强致畸性和致癌性的重金属. 为研究镉暴露对早期胚胎发育的毒性效应,以斑马鱼为模式动物,选取5个镉浓度来处理斑马鱼胚胎4~120 hpf (hours post fertilization, 受精后小时),计算镉的半致死(LC50)浓度,研究7.50 mg/L镉对斑马鱼胚胎8个基因表达的影响. 结果表明:镉暴露导致斑马鱼胚胎产生小头、小眼、躯干弯曲、心脏发育异常以及死亡等异常. 通过原位杂交和定量PCR方法分析镉对抗氧化基因(prdx1gstp1.2)、转录翻译相关基因(atf3jdp2beif4a1b)、应激反应相关基因(hsp70lhsp90aa1.1)以及脂肪酸结合蛋白基因(fabp7a)表达的影响,发现镉暴露将改变上述基因在组织和器官的表达及表达水平,这些影响可能与镉导致斑马鱼胚胎嗅球、侧线、神经和心脏的发育异常有关. 研究显示,镉的LC50浓度为15.20 mg/L,7.50 mg/L的镉可影响斑马鱼胚胎的氧化应激、转录翻译和早期神经发育等过程,并通过影响基因表达从而干扰斑马鱼胚胎发育,进而可能造成个体嗅觉、视觉和运动等功能缺陷.

     

    Abstract: Cadmium is a heavy metal with strong teratogenic and carcinogenic properties. To investigate the developmental toxicity, we exposed zebrafish embryos to 5 different concentrations of cadmium from 4 to 120 hpf (hours post fertilization) and calculated the 50% lethality concentration (LC50). To determine the changes in gene expression associated with cadmium, embryos were exposed to 7.50 mg/L cadmium from 4 to 48 hpf, and whole mount in situ hybridization and quantitative PCR were performed. The results showed that cadmium caused malformation in zebrafish embryos such as small heads and eyes, spinal curvature, abnormal development of heart and death. The changes in expression of genes encoding antioxidant genes peroxiredoxin 1 (prdx1) and glutathione S-transferase pi 1.2 (gstp1.2), related with transcription and translation genes activating transcription factor 3 (atf3), jun dimerization protein 2b (jdp2b),and eukaryotic translation initiation factor 4A1B (eif4a1b), stress rensponse-related genes heat shock cognate 70-kd protein, like (hsp70l), heat shock protein 90, alpha (cytosolic), class A member 1, tandem duplicate 1 (hsp90aa1.1) and fatty acid binding protein brain a (fabp7a) were observed in embryos exposed to cadmium. These effects may be related to the unusual development of the olfactory bulb, lateral line, nerve system and heart of zebrafish embryos. Our study shows that the LC50 of cadmium is 15.20 mg/L. Exposure of 7.50 mg/L cadmium induces the oxidative stress, affects transcription and translation, and early neurodevelopment of zebrafish embryos, and interferes with the development of zebrafish embryos by affecting gene expression regions, which may lead to functional defects, such as smell, vision, and movement.

     

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