Post-graduate Program in Animal Biology, Department of Biology, São Paulo State University (UNESP), São José do Rio Preto, São Paulo, 15054-000, Brazil.
Instituto de Biodiversidad y Biología Experimental y Aplicada-CONICET, C1428EGA, Autonomous City of Buenos Aires, Argentina.
Environ Sci Pollut Res Int. 2019 Aug;26(22):22209-22219. doi: 10.1007/s11356-019-05403-8. Epub 2019 May 31.
Endocrine disrupting chemicals are one of the most important factors contributing to worldwide amphibian decline. The 4-nonylphenol (NP) is a degradation product of several compounds, such as detergents and pesticides, affecting the aquatic environment. Here, we test whether treatment with NP has an effect on developing ovarian tissue, nuclear abnormalities in erythrocytes, and body darkness in pre-metamorphic tadpoles of the bullfrog Lithobates catesbeianus. Tadpoles were exposed for 14 days to three different concentrations of NP (1, 10, and 100 μg/L) besides the control group, which was maintained only with water. After determining body coloration, animals were euthanized and gonads and blood were collected and processed for histology and genotoxic analysis. Even though most animals were females, intersex tadpoles were observed in control and treated groups and there were no males in any group. The highest concentration of NP showed an increase in atretic oocytes, but the area corresponding to somatic compartment and early and late germ cells were not affected. Furthermore, all treated groups presented higher amount of nuclear abnormalities in erythrocytes and body darkening when compared with the control group. These results suggest that NP causes genetic damage and morphological alterations in L. catesbeianus tadpoles by disrupting oogenesis, inducing genotoxicity and increasing body coloration. Its effects on gonadal development could cause future impairments in reproduction, while its deleterious effects on genotoxicity and body pigmentation could be used as a biomarker of effect to this compound.
内分泌干扰化学物质是导致全球两栖动物数量下降的最重要因素之一。壬基酚（NP）是几种化合物如清洁剂和农药的降解产物，会影响水生环境。在这里，我们测试了 NP 是否会对发育中的卵巢组织、红细胞核异常以及处于前变态期的牛蛙 Lithobates catesbeianus 幼体的身体颜色产生影响。幼体在 14 天内暴露于三种不同浓度的 NP（1、10 和 100μg/L）中，除了仅用水维持的对照组。在确定体色后，处死动物并收集性腺和血液，进行组织学和遗传毒性分析。尽管大多数动物是雌性，但在对照组和处理组中观察到了间性幼体，而任何组都没有雄性。最高浓度的 NP 显示出闭锁卵母细胞的增加，但体细胞和早期及晚期生殖细胞的相应区域不受影响。此外，与对照组相比，所有处理组的红细胞核异常和体色加深的数量都增加。这些结果表明，NP 通过干扰卵母细胞发生、诱导遗传毒性和增加体色，导致 L. catesbeianus 幼体发生遗传损伤和形态改变。它对性腺发育的影响可能会导致未来繁殖受损，而其对遗传毒性和身体色素沉着的有害影响可作为该化合物效应的生物标志物。
