Schmidt Florian, Braunbeck Thomas
Aquatic Ecology and Toxicology Group, Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany.
J Thyroid Res. 2011;2011:376243. doi: 10.4061/2011/376243. Epub 2011 Aug 9.
In the past, various approaches have been developed to detect adverse effects of pollutants on the thyroid of vertebrates, most of these with special emphasis on the South African clawed frog, Xenopus laevis. Although fish are primarily affected by thyroid-disrupting chemicals, studies into alterations of the thyroid of fish are scarce. Therefore, effects of the reference compound propylthiouracil on histopathology of the thyroid axis were analyzed in a modified early life-stage test with zebrafish (Danio rerio) exposed to propylthiouracil. The test substance induced dose-dependent alterations of thyroidal tissue concomitant with increases in the number of surrounding blood vessels. Despite this massive proliferation of the thyroid, zebrafish were not able to maintain thyroxin concentrations. The pituitary was affected displaying significant alterations in thyroid-stimulating hormone cell counts. Quantitative evaluation of pituitary surface areas revealed a dose-dependent increase of adenohypophyseal tissue. Distinct histopathological effects may contribute to a more easy identification and interpretation of alterations induced by thyroid-disrupting chemicals.
过去,人们已开发出各种方法来检测污染物对脊椎动物甲状腺的不良影响,其中大多数特别关注南非爪蟾(非洲爪蟾)。尽管鱼类主要受甲状腺干扰化学物质的影响,但对鱼类甲状腺变化的研究却很少。因此,在一项改良的早期生命阶段试验中,分析了参考化合物丙硫氧嘧啶对斑马鱼(斑马鱼)甲状腺轴组织病理学的影响,该试验中斑马鱼暴露于丙硫氧嘧啶。受试物质引起甲状腺组织的剂量依赖性变化,并伴有周围血管数量的增加。尽管甲状腺大量增殖,但斑马鱼无法维持甲状腺素浓度。垂体受到影响,促甲状腺激素细胞计数出现显著变化。垂体表面积的定量评估显示腺垂体组织呈剂量依赖性增加。明显的组织病理学效应可能有助于更轻松地识别和解释由甲状腺干扰化学物质引起的变化。