Kamata Ryo, Takahashi Shinji, Shimizu Akira, Morita Masatoshi, Shiraishi Fujio
Research Center for Environmental Risk, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan.
Arch Toxicol. 2006 Dec;80(12):857-67. doi: 10.1007/s00204-006-0113-1.
Although there are in vivo assays using various organisms for the risk assessment of chemicals with endocrine disrupting properties, effective experimental methods for avian species are still under debate. We have developed an in ovo exposure assay using Japanese quail eggs, aimed at assessing disrupting effects on avian reproductive development and function. Hybrid eggs from Brazilian Brown male and White Egg female quails, which can be genetically sexed by their plumage color after hatching, were prepared, and test materials dissolved in olive oil were injected into the air-chamber on day 10 of incubation. After sexual maturation of hatched chicks, we observed egg production by females and the egg quality and male-typical reproductive behavior, and then examined reproductive system morphology and serum steroid concentrations in both sexes. Treatment with a synthetic estrogen, diethylstilbestrol (DES, 0.5-50 ng/g egg), dose-dependently reduced the eggshell thickness and strength of eggs. A few females treated with 5 ng/g DES per egg produced soft-shelled/ unmarked eggs, and all laying females treated with 50 ng/g egg produced eggs completely lacking shells. DES also induced shortening of the left oviduct and abnormal development of the right oviduct in a dose-dependent manner, while testis weight was reduced symmetrically. In addition, 2,2',4',6'-tetrachlorobiphenyl-4-ol (10-1,000 ng/g egg), which previously showed relatively high estrogenic activity in vitro, caused dose-dependent shortening of the left oviduct and reduction in testis weight. The methods for evaluating endocrine disrupting effects and preparing experimental birds proposed in the present study are expected to facilitate assays for avian reproductive toxicology.
尽管存在多种利用不同生物体进行具有内分泌干扰特性化学品风险评估的体内试验，但针对鸟类的有效实验方法仍存在争议。我们开发了一种利用日本鹌鹑蛋进行的胚胎期暴露试验，旨在评估对鸟类生殖发育和功能的干扰作用。制备了巴西棕雄鹌鹑和白蛋雌鹌鹑的杂交蛋，这些蛋孵化后可根据羽毛颜色进行基因性别鉴定，并在孵化第10天，将溶解于橄榄油中的测试材料注入气室。在孵化出的雏鸡性成熟后，我们观察了雌性的产蛋情况、蛋的质量以及雄性典型的生殖行为，然后检查了两性的生殖系统形态和血清类固醇浓度。用合成雌激素己烯雌酚（DES，0.5 - 50 ng/g蛋）处理后，蛋的蛋壳厚度和强度呈剂量依赖性降低。每枚蛋用5 ng/g DES处理的少数雌性产出软壳/无斑纹蛋，而每枚蛋用50 ng/g DES处理的所有产蛋雌性产出的蛋完全没有蛋壳。DES还以剂量依赖性方式诱导左输卵管缩短和右输卵管发育异常，同时睾丸重量对称减轻。此外，先前在体外显示出相对较高雌激素活性的2,2',4',6'-四氯联苯-4-醇（10 - 1,000 ng/g蛋）导致左输卵管剂量依赖性缩短和睾丸重量减轻。本研究中提出的评估内分泌干扰作用的方法和制备实验鸟类的方法有望促进鸟类生殖毒理学的试验。
