【作者】 刘阿朋；

【导师】 王卫民； 王子健；

【作者基本信息】 华中农业大学 ， 水产养殖， 2006， 硕士

【摘要】 本论文通过环境内分泌干扰物17α-甲基睾酮(17α-MT)和三丁基锡氧化物(TBTO)对稀有鮈鲫(Rare Minnow，Gobiocypris rarus)不同生命阶段的暴露，研究它们在环境浓度范围内对稀有鮈鲫的影响，从生长、组织学和卵黄蛋白原含量方面探讨对稀有鮈鲫的内分泌干扰效应和生物毒性，并比较稀有鮈鲫不同生命阶段对内分泌干扰物暴露检测的敏感性，主要内容如下：在实验室模拟自然环境使用不会带来污染的材料和设备建立了稀有鮈鲫流水养殖系统和流水暴露系统，符合美国环境保护局关于内分泌干扰物生物检测的实验标准，探索和规范了稀有鮈鲫培育方法，为实验室进行鱼类毒理学试验提供了适合的试验材料，保证了实验结果的准确性和可靠性。稀有鮈鲫不同生命阶段的暴露表明：在胚胎发育阶段，17α-MT暴露后稀有鮈鲫胚胎发育没有延缓，没有胚胎死亡现象，17α-MT暴露对稀有鮈鲫胚胎发育没有生物毒性；在性分化阶段和未成熟至成熟阶段，17α-MT能促进雄性稀有鮈鲫的性腺发育，表现出雄激素效应，50ng／L以上浓度的17α-MT可诱导性分化阶段稀有鮈鲫血浆中产生卵黄蛋白原，可能是17α-MT转变为17α-ME而表现出类雌激素效应，17α-MT暴露后没有对此阶段稀有鮈鲫的生长产生影响，对鳃、肝和肾组织没有细胞毒性；在成熟阶段，雌性稀有鮈鲫血浆卵黄蛋白原含量随17α-MT浓度增加而下降，稀有鮈鲫体内卵黄蛋白原的合成受到抑制，表现出内分泌干扰效应，17α-MT暴露后对稀有鮈鲫生长没有影响。TBTO对稀有鮈鲫各生命阶段暴露后，在胚胎发育阶段没有表现出内分泌干扰效应和生物毒性，稀有鮈鲫胚胎发育没有受到抑制，没有胚胎死亡现象，所有胚胎都能正常发育；在性分化阶段，TBTO对稀有鮈鲫的精巢发育有促进作用，表现出类雄激素效应，稀有鮈鲫的鳃上皮细胞增生，肝细胞出现空泡化，肾小管上皮细胞出现增生、肥大，对各组织表现出较强的生物毒性，TBTO暴露后没有对此阶段稀有鮈鲫的生长造成影响；在未成熟至成熟阶段和成熟阶段，16ng／L以上浓度的TBTO暴露后稀有鮈鲫肝脏受到一定的损伤，肝细胞出现空泡化，表现出生物毒性，TBTO暴露后没有对稀有鮈鲫体内卵黄蛋白原合成产生影响，TBTO暴露后没有对未成熟至成熟和成熟阶段稀有鮈鲫生长产生影响。比较稀有鮈鲫不同生命阶段暴露结果，发现不同生命阶段对17α-MT和TBTO暴露的敏感性不同，性分化阶段为最敏感阶段，其次为未成熟阶段和成熟阶段，胚胎发育阶段对内分泌干扰物的敏感性较差，不适合进行内分泌干扰物测试。TBTO暴露后稀有鮈鲫鳃和肝脏的损伤严重，可以作为检测环境内分泌干扰物毒性效应的组织器官。更多还原

【Abstract】 The experiment was conducted to evaluate the impact of environmental endocrine disruptors, 17α-Methyltestosterone and Bis(tributyltin)oxide, on biology of rare minnow (Gobiocypris rarus). The fish, at different life stages, was exposed to 17α-Methyltestosterone and Bis(tributyltin)oxide, at concentration levels closed to environmental conditions. Embryonic development, growth, hispathology and vitellogenine analysis was used to investigate endocrine disruption effect and biotoxicity of 17α-Methyltestosterone and Bis(tributyltin)oxide, and comparative sensitivity of the fish at different life stages.Water flow through controlled system and the exposure system was set up in laboratory simulating natural environment. For the sake of accuracy, the materials and equipment were made pollution free in accordance with endocrine disruptor’s bioassay standard of US Environmental Protection Agency. The culture methodology of rare minnow was established according to laboratory scale, which provided a system enough for fish toxicology experiments. The relevant conditions were adjusted so as to assure the accuracy and reliability of results.The results of present research endeavor reveal that 17α-Methyltestosterone has no toxic effect upon the embryonic development of rare minnow. During experimental exposure, fish embryo developed normally and no embryonic mortality was observed. At sexual differentiation stage and fry-to-fish stage of rare minnow, 17α-Methyltestosterone showed androgenetic effect and promoted gonad development. Plasma vitellogenin was induced during sexual differentiation stage at exposure concentration higher than 50ng/L. It may have been caused due to conversion of 17α-Methyltestosterone into 17α-Methylestradiol, which showed estrogen effect. The growth of rare minnow was not affected and there was no cytotoxicity in hepatic, renal and gill tissues after exposure to 17α-Methyltestosterone. Increased exposure concentration of 17α-Methyltestosterone showed a negative impact on the plasma vitellogenine contents of adult female fish. Vitellogenine synthesis was suppressed due to endocrine disruption effect of 17α-Methyltestosterone but with no impact on the growth of adult fish.The results of exposure to Bis(tributyltin)oxide showed that also, there was no endocrine disruption and biotoxicity observed at embryonic development stage of rare minnow. The embryo development was not inhibited, and no embryo mortality was observed. All the embryos developed normally. At sexual differentiation stage and fry-to-fish stage of rare minnow, Bis(tributyltin)oxide showed androgen effect spermary development of the fish was promoted. The epithelial cells of gills and nephric tubules proliferated and showed hypertrophic growth. In adult fish, at exposure concentration higher than 16ng/L, hepatic tissues showed lesions and hepatic cells were found to be vacuolar. The results indicate that Bis(tributyltin)oxide had a strong biotoxic impact upon the fish tissues. Vitellogenine synthesis and growth of the fish were not affected throughout the exposure duration.Comparative sensitivity at different life stages of rare minnow to exposure of environmental endocrine disruptors, 17α-Methyltestosterone and Bis(tributyltin)oxide, was different at every stage. Sexual differentiation stage of rare minnow was found to be the most sensitive stage, followed by the fry and adult stage. Sensitivity of embryonic development stage of rare minnow to exposure of environmental endocrine disruptors was not significant. Hepatic and gill tissue were badly affected by the exposure to Bis(tributyltin)oxide concluding that these tissues could be used as test specimen to investigate the biotoxic effect of exposure to environmental endocrine disruptors.更多还原