Department of Pediatrics, Nanjing Medical University, NO.140, Hanzhong Road, Nanjing 210029, China; Department of Pediatrics, Nanjing Maternity and Child Health Care Hospital of Nanjing Medical University, NO.123, Tianfei Road, Mochou Street, Nanjing 210004, China.
Department of Pediatrics, Nanjing Maternity and Child Health Care Hospital of Nanjing Medical University, NO.123, Tianfei Road, Mochou Street, Nanjing 210004, China.
Ecotoxicol Environ Saf. 2015 Aug;118:133-138. doi: 10.1016/j.ecoenv.2015.04.026. Epub 2015 May 4.
Polychlorinated biphenyls (PCBs), a group of highly toxic environmental pollutants, have been report to influence the visual system development in children. However, the underlying mechanism is unclear. The study was aim to investigate the effects of continuous PCBs exposure on optomotor response (OMR) and retinal photoreceptor cell development-related gene expression in zebrafish larvae. The fertilized zebrafish embryos were exposed to PCBs at concentrations of 0.125, 0.25, 0.5, and 1mg/L until 7 days post-fertilization. Control groups with blank and 0.01% methanol were also prepared. OMR test was used to detect the visual behavior. The mRNA expression of the CRX, RHO, SWS1, and SWS2 was assessed by the Quantitative Real-Time PCR. The OMR test showed that the visual behavior of the larvae was most sensitive when the grating spatial frequency was 0.20LP/mm and the moving speed was 25cm/s. Moreover, the proportion of positively swimming fish was significantly reduced in the 0.5 and 1mg/L PCB1254 treatment group (P<0.05) compared with the controls. In addition, the expression of SWS2 was significantly down-regulated in all PCB1254 treatment groups (P<0.05), whereas the decreased expression of the CRX, RHO and SWS1 was found in the 0.5 and 1mg/L PCB1254 groups (P<0.05). This is the first report to demonstrate that continue exposure of zebrafish larvae to PCBs causes photoreceptor cell development-related gene expression changes that lead to OMR behavioral alterations. Analysis of these visual behavioral paradigms may be useful in predicting the adverse effects of toxicants on visual function in fish.
多氯联苯（PCBs）是一组高度有毒的环境污染物，据报道会影响儿童的视觉系统发育。然而，其潜在机制尚不清楚。本研究旨在探讨连续暴露于 PCBs 对斑马鱼幼鱼光感受器细胞发育相关基因表达和光感受器反应（OMR）的影响。将受精后的斑马鱼胚胎暴露于浓度为 0.125、0.25、0.5 和 1mg/L 的 PCBs 中，直到受精后 7 天。还制备了空白和 0.01%甲醇的对照组。使用光感受器反应测试来检测视觉行为。通过定量实时 PCR 评估 CRX、RHO、SWS1 和 SWS2 的 mRNA 表达。OMR 测试表明，当空间频率为 0.20LP/mm、移动速度为 25cm/s 时，幼鱼的视觉行为最敏感。此外，与对照组相比，在 0.5 和 1mg/L PCB1254 处理组中，正向游动鱼的比例显著降低（P<0.05）。此外，所有 PCB1254 处理组的 SWS2 表达均显著下调（P<0.05），而在 0.5 和 1mg/L PCB1254 组中发现 CRX、RHO 和 SWS1 的表达减少（P<0.05）。这是首次报道表明，斑马鱼幼鱼持续暴露于 PCBs 会导致光感受器细胞发育相关基因表达变化，从而导致 OMR 行为改变。分析这些视觉行为范式可能有助于预测毒物对鱼类视觉功能的不良影响。
