National Institute of Nutrition and Research (NIFES) Pb. 2029 Nordnes, 5817 Bergen, Norway.
Aquat Toxicol. 2012 Feb;108:70-7. doi: 10.1016/j.aquatox.2011.08.017. Epub 2011 Aug 27.
Methylmercury (MeHg) is an environmental contaminant most known for its severe neurotoxic effects. Although accumulation of MeHg tends to be several folds higher in kidney compared to other tissues, studies on nephrotoxic effects are almost non-existing. In this study we aim to investigate the toxicity of dietary MeHg in kidney of Atlantic salmon (Salmo salar).
Atlantic salmon were exposed to dietary MeHg for a period of 8 weeks, before the fish were euthanized and kidney was sampled for proteomic and real time RT-PCR analysis, as well as for mercury determination. Protein separation was done with 2-D PAGE, and differentially regulated spots were picked for analysis using liquid chromatography MS/MS analysis. Moreover, whole blood and liver tissue were sampled for mercury determination and real time RT-PCR (liver).
MeHg exposed fish accumulated significantly more mercury (Hg) than control fish. The proteomic analysis revealed differential abundance of 26 spots in the kidney, and 14 of these protein spots were successfully identified. The proteins identified indicated effects of MeHg on; metabolism, inflammation, oxidative stress, protein-folding, and cell-structural components. Gene expression analysis of selected markers revealed few differentially regulated transcripts in kidney and liver in the exposed fish compared to the control fish. However, the affected transcripts indicated a disruption in the expression of two metabolic markers due to MeHg exposure in liver.
This study suggests that dietary MeHg has similar effects in kidney as previously shown for other tissues in fish. The effects observed were in markers for oxidative stress, inflammation and energy metabolism. The identification of proteomic markers in this study provides a basis for a better understanding of MeHg-induced nephrotoxicity in fish.
甲基汞（MeHg）是一种环境污染物，以其严重的神经毒性而闻名。尽管与其他组织相比，肾脏中 MeHg 的积累往往高出数倍，但关于其肾毒性的研究几乎不存在。在这项研究中，我们旨在研究饮食中 MeHg 对大西洋鲑鱼（Salmo salar）肾脏的毒性。
大西洋鲑鱼在食用 MeHg 8 周后，被安乐死，然后采集肾脏样本进行蛋白质组学和实时 RT-PCR 分析，以及汞含量测定。蛋白质分离采用二维 PAGE 进行，差异调节斑点用于液相色谱 MS/MS 分析。此外，还采集全血和肝组织进行汞含量测定和实时 RT-PCR（肝脏）。
暴露于 MeHg 的鱼体内积累的汞（Hg）明显多于对照组。蛋白质组学分析显示，肾脏中有 26 个斑点的丰度存在差异，其中 14 个蛋白质斑点成功被鉴定。鉴定出的蛋白质表明，MeHg 对代谢、炎症、氧化应激、蛋白质折叠和细胞结构成分产生影响。对选定标志物的基因表达分析显示，与对照组相比，暴露组的鱼肾和肝中仅有少数转录本发生差异调节。然而，受影响的转录本表明，由于 MeHg 暴露，肝脏中两种代谢标志物的表达出现紊乱。
本研究表明，饮食中 MeHg 对肾脏的影响与先前在鱼类其他组织中观察到的相似。观察到的影响涉及氧化应激、炎症和能量代谢的标志物。本研究中蛋白质组学标志物的鉴定为更好地理解鱼类中 MeHg 诱导的肾毒性提供了基础。
