慢性低质量浓度多氯联苯暴露对斑马鱼视网膜形态学的影响

Effects of Long-Term Exposure to Polychlorinated Biphenyls of Low Concentrations on Morphology Development of Zebrafish Retinal

目的探讨慢性低质量浓度多氯联苯(PCBs)暴露对斑马鱼视网膜形态学发育的影响。方法以斑马鱼为模式生物,持续低质量浓度(0.05 mg.L-1)PCBs对斑马鱼胚胎进行暴露处理(实验组),同时设正常对照组。收集受精后7 d(7 dpf)、15 d(15dpf)及30 d(30 dpf)斑马鱼幼鱼,通过光镜和电镜技术,观察各组视网膜不同发育阶段结构形态学的变化。结果 1.光镜下:7 dpf和15 dpf,实验组斑马鱼视网膜各层厚度、细胞排列、细胞形态无明显影响。30 dpf时,实验组斑马鱼部分感光细胞出现核染色质边聚,空泡化变性,胞核变稀疏。2.透射电镜观察:7 dpf和15 dpf时,实验组斑马鱼视网膜感光细胞外节盘结构无明显影响。30 dpf时,实验组斑马鱼视网膜感光细胞有正常外节段形成,但较正常对照组小,且数量变少,线粒体空泡化变性,内质网扩张。结论日常生活中的慢性低质量浓度PCBs暴露对斑马鱼视网膜发育产生毒害作用,因此,必须加强对环境有机污染物的监测和控制。提示环境中长期存在低质量浓度PCBs暴露对人群健康可能造成一定的影响。

Objective To explore the effects of low concentration of polychlorinated biphenyls （PCBs） on zebrafish retinal morphology which were exposed to it for a long time. Methods The zebrafishes were divided into normal ones （ normal control group） and 0.05 mg · L^-1 PCBs treatment ones（ experimental group）. The retinal morphology changes of zebrafish embryos were observed by light and electron microscope after 7,15,30 days separately. Results 1. Under the light microscope ： There was no significant difference on the zehrafish retinal morphology between the 2 groups after 7 days and 15 days, while nuclear chromatin margination, cell vacuolization and reducement of the nuclear numbers were observed after 30 days. 2. Under the electronic microscope ：There was no obvious influence on the outer segment disk of retinal photoreceptor after 7 days and 15 days in experimental group,while less and smaller outer segment disk of retinal photoreceptor, mitochondrial vacuolization and degeneration and the endoplasmic reticulum expansion were observed after 30 days treatment. Conclusions Long - time exposure to low concentrations of PCBs in daily life will do harm to zebrafish retinal development,thus, should be strengthen the monitoring and controlling of organic pollutants in the environment. At the same time,the presence of low concentrations of PCBs around may also have a certain imoact on population health.