This research investigated the adverse effects of neonicotinoids on the Northwestern salamander (Ambystoma gracile; NWS) after acute and subchronic exposures during early aquatic life stages via whole organism (i.e., growth, development) and molecular (i.e., gene expression) level endpoints. In a 96-h exposure, NWS larvae were exposed to four imidacloprid concentrations (250, 750, 2250, 6750 µg/L) and a water control treatment, and no effects on survival, body weight, snout-vent length (SVL), and total body length were observed. However, a significant 1.70- and 2.33-fold decrease in thyroid receptor β (TRβ) mRNA expression levels were detected in the larvae exposed to 750 and 2250 µg/L imidacloprid, respectively, compared with the larvae in the water control. In subsequent subchronic experiments, NWS larvae were exposed for 35 days to imidacloprid alone and an equal part mixture of neonicotinoids (imidacloprid, clothianidin, and thiamethoxam (ICT)) at three concentrations (10, 100 and 1000 µg total neonicotinoids/L) and a water control. In these experiments, there were no effects on larval survival, body weight, SVL, and total body length. However, advanced development of larvae in the 100 µg/L imidacloprid treatment was observed compared with the control after 35-day imidacloprid exposure, providing some evidence of disruption of the thyroid endocrine axis at an environmentally relevant concentration. Ultimately, there is a paucity of studies conducted examining the sensitivity of salamanders to pollutants; thus, this study reports novel findings that will contribute to understanding the sensitivity of a Caudate amphibian model to a common environmental pollutant.

这项研究调查了新烟碱类药物对西北sal（Ambystoma gracile）的不利影响; 在整个水生生物阶段（即生长，发育）和分子（即基因表达）水平终点，在水生生命早期经历急性和亚慢性暴露后。在96小时的暴露中，将NWS幼虫暴露于四种吡虫啉浓度（250、750、2250、6750 µg / L）和水控制处理，对存活率，体重，口鼻长度（SVL）无影响，和全身长度被观察到。然而，与水对照中的幼虫相比，暴露于750和2250 µg / L吡虫啉的幼虫中的甲状腺受体β（TRβ）mRNA表达水平分别下降了1.70倍和2.33倍。在随后的亚慢性实验中，将新创建的幼虫分别暴露于吡虫啉和等份的新烟碱类混合物（吡虫啉，可比尼丁，和噻虫嗪（ICT））分别以三种浓度（总新烟碱含量为10、100和1000 µg / L）和水质控制。在这些实验中，对幼虫存活率，体重，SVL和总体长没有影响。但是，与吡虫啉接触35天后的对照组相比，在100 µg / L吡虫啉处理中观察到了幼虫的晚期发育，这提供了一些在环境相关浓度下破坏甲状腺内分泌轴的证据。最终，很少有研究检查sal对污染物的敏感性。因此，本研究报告了一些新颖的发现，这些发现将有助于理解尾状两栖动物模型对常见环境污染物的敏感性。对幼虫的存活率，体重，SVL和总体长没有影响。但是，与吡虫啉接触35天后的对照组相比，在100 µg / L吡虫啉处理中观察到了幼虫的晚期发育，这提供了一些在环境相关浓度下破坏甲状腺内分泌轴的证据。最终，很少有研究检查sal对污染物的敏感性。因此，本研究报告了一些新颖的发现，这些发现将有助于理解尾状两栖动物模型对常见环境污染物的敏感性。对幼虫的存活率，体重，SVL和总体长没有影响。但是，与吡虫啉接触35天后的对照组相比，在100 µg / L吡虫啉处理中观察到了幼虫的晚期发育，这提供了一些在环境相关浓度下破坏甲状腺内分泌轴的证据。最终，很少有研究检查sal对污染物的敏感性。因此，本研究报告了一些新颖的发现，这些发现将有助于理解尾状两栖动物模型对常见环境污染物的敏感性。在环境相关浓度下提供一些破坏甲状腺内分泌轴的证据。最终，很少有研究检查sal对污染物的敏感性。因此，本研究报告了一些新颖的发现，这些发现将有助于理解尾状两栖动物模型对常见环境污染物的敏感性。在环境相关浓度下提供一些破坏甲状腺内分泌轴的证据。最终，很少有研究检查sal对污染物的敏感性。因此，本研究报告了一些新颖的发现，这些发现将有助于理解尾状两栖动物模型对常见环境污染物的敏感性。